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spores

spores Sentence Examples

  • Such applications at the momelit when spores are germinating on the leaves, e.g.

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  • Such applications at the momelit when spores are germinating on the leaves, e.g.

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  • The danger from this source is remote, as the microbe does not form spores within the animal body.

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  • Milk so treated will keep at the ordinary room temperature, as the spores of the B.

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  • In most cases four spores are formed within the cell by free formation.

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  • The lactic acid bacillus, always present in unboiled milk (to which the souring of milk is due), is easily destroyed by heat; but the bacillus mesentericus, often found in it, forms spores, which are not destroyed by ordinary boiling, and germinate when the milk is kept at a moderately warm temperature, producing a brisk fermentation whereby a large volume of gas is liberated.

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  • The lactic acid bacillus, always present in unboiled milk (to which the souring of milk is due), is easily destroyed by heat; but the bacillus mesentericus, often found in it, forms spores, which are not destroyed by ordinary boiling, and germinate when the milk is kept at a moderately warm temperature, producing a brisk fermentation whereby a large volume of gas is liberated.

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  • When a mushroom is perfectly ripe and the gills are brown-black in colour, they throw down a thick dusty deposit of fine brown-black or purple-black spores; it is essential to note the colour.

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  • The inner coat enveloping the spores is supported, like a ball, either with or without a stalk on the upper face of the star.

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  • The inner coat enveloping the spores is supported, like a ball, either with or without a stalk on the upper face of the star.

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  • no spores make their appearance, the yeast in question may be regarded as S.

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  • A "map" of the spores should be taken by separating a pileus and placing it flat on a piece of thin paper for a few hours when the spores will fall and leave a nature print of the arrangement of the gills which may be fixed by gumming the other side of the paper.

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  • Schwann in 1839) was studied by Hansen, who found that each species only developed spores between certain definite temperatures.

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  • The seeds of the cryptogams or flowerless plants are not true seeds and are properly designated "spores."

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  • The primary function of the flower is to bear the spores.

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  • Schwann in 1839) was studied by Hansen, who found that each species only developed spores between certain definite temperatures.

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  • The mycelium produced from the spores dropped by the fungus or from the "spawn" in the soil, radiates outwards, and each year's successive crop of fungi rises from the new growth round the circle.

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  • The true mushroom itself is to a great extent a dung-borne species, therefore mushroom-beds are always liable to an invasion from other dung-borne forms. The spores of all fungi are constantly floating about in the air, and when the spores of dung-infesting species alight on a mushroom-bed they find a nidus already prepared that exactly suits them; and if the spawn of the new-comer becomes more profuse than that of the mushroom the stranger takes up his position at the expense of the mushroom.

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  • The common mushroom (Agaricus campestris) is propagated by spores, the fine black dust seen to be thrown off when a mature specimen is laid on white paper or a white dish; these give rise to what is known as the "spawn" or mycelium, which consists of whitish threads permeating dried dung or similar substances, and which, when planted in a proper medium, runs through the mass, and eventually develops the fructification known as the mushroom.

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  • The spores differ from those of ferns in their outer coat (exospore) being split up into four club-shaped hygroscopic threads (elaters) which are curled when moist, but become straightened when dry.

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  • The plant world falls into two great divisions, the higher or flowering plants (Phanerogams), characterized by the formation of a seed, and the lower or flowerless plants (Cryptogams), in which no seed is formed but the plants are disseminated by means of unicellular bodies termed spores.

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  • The spores, as in the heterosporous Pteridophyta, are of two kindsmicrospores (pollen grains) borne in microsporangia (pollen sacs) on special leaves (sporophylls) known as stamens, and macrospores (embryo-sac) borne in macrosporangia (ovules) on sporophylls known as carpels.

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  • The simpler Fungi, like the simpler Green Algae, consist of single cells or simple or branched cell-threads, but among the higher kinds a massive body is often formed, particuTissue t~Jf larly in con nexion with the formation of spores, and, er~n,~,onthiS may exhibit considerable tissue-differentiation.

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  • The sporogonium of the liverworts is in the simpler forms simply a spore-capstile with arrangements for the development, protection and distribution of the spores.

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  • ferns, horse-tails, club mosses, &c., and Phanerogams or Flowering Plants) the main plant-body, that which we speak of in ordinary language as the plant, is called the sporophyte because it bears the asexual reproductive cells or spores.

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  • For instance, a Fungus epidemic is impossible unless the climatic conditions are such as to favor the dispersal and germination of the spores; and when plants are killed off owi~ig to the supersaturation of the soil with water, it is by no means obvious whether the excess of water and dissolved materials, or the exclusion of oxygen from the root-hairs, or the lowering of the temperature, or the accumulation of foul products of decomposition should be put into the foreground.

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  • The spores of Rusts, Erysipheae an d other Fungi may be conveyed from plant to plant by snails; those of tree-killing polyporei, &c., by mice, rabbits, rats, &c., which rub their fur against the hymenophores.

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  • Bees carry the spores of Scierotinia as they do the pollen of the bilberries, and flies convey the conidia of ergot from grain to grain.

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  • Worms bring spores to the surface of soil, ducks and other birds convey them on their muddy feet.

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  • Erysiphe, or the steeping in hot water of thoroughly ripe hard grains to which spores are attached, e.g.

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  • those due to .Synchytrium, Protomyces, Cysto pus, many Ustilagineae, &c. These cases are not easily distinguished superficially froni the pustular outgrowth of actual mycelia and spores (stromata) of such Fungi as Nectria, Puccinia, &c. The cylindrical stem-swellings due to Calyptospora, Epichloe, &c., may also be mentioned here, and the tyro may easily confound with these the layers and cushions of eggs laid on similar organs by moths.

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  • In the Thallophytes the cytoplasm may be segmented by constriction, due to the in-growth of a new cell wall from the old one, as in Spirogyra and Cladophora, or by the formation of cleavage furrows in which the new cell-wall is secreted, as occurs in the formation of the spores in many Algae and Fungi.

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  • In a few cases both among the higher and the lower plants, of which the formation of spores in the ascus is a typical example, new cells are formed by the aggregation of portions of the cytoplasm around the nuclei which become delimited from the rest of the cell iontents by a membrane.

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  • Accepting this view of the phylogeny of the leaf, the perianthleaves (sepals and petals) and the foliage-leaves may be regarded as modified or metamorphosed sporophylls; that is, as leaves which are adapted to functions other than the bearing of spores.

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  • "He saw that they increased in size, divided, and became full of filiform spores, then ruptured and poured out their multitudinous progeny into the bodycavity of their insect host.

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  • Gymnosporangium sabinae, one of the rusts (Uredineae) passes one stage of its life-history on living pear leaves, forming large raised spots or patches which are at first yellow but soon become red and are visible on both faces; on the lower face of each patch is a group of cluster-cups or aecidia containing spores which escape when ripe.

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  • This stage in the life-history was formerly regarded as a distinct fungus with the name Roestelia cancellata; it is now known, however, that the spores germinate on young juniper leaves, in which they give rise to this other stage in the plant's history known as Gymnosporangium.

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  • The gelatinous, generally reddish-brown masses of spores - the teleutospores - formed on the juniper in the spring germinate and form minute spores - sporidia - which give rise to the aecidium stage on the pear.

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  • The fungus mycelium grows between the cuticle and the epidermis, the former being ultimately ruptured by numerous short branches bearing spores (conidia) by means of which the disease is spread.

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  • Pear trees may 2, Section of leaf surface showing the also be attacked by a great spores or conidia, c, borne on long variety of insect pests.

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  • aaK6s, a bag), a botanical term for the membranous sacs containing the reproductive spores in certain lichens and fungi.

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  • The presence of the volva, and the clear white gills and spores, distinguish this genus from all other agarics.

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  • Portion of the mycelium of the fungus bearing spores (conidia), s, on erect branches, X250.

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  • Ascus from perithecium containing six spores, X30o.

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  • These are minute, oval, colourless spores, which serve to spread the disease over the vineyard and from place to place.

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  • Single ascus, more enlarged, showing the eight contained spores.

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  • Cercospora Vitis (Cladosporium viticolum), which has club-shaped spores of a green-brown colour, also attacks the leaves; but, unless the season is extremely unfavourable, it does little harm.

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  • The latter is the more serious, as in addition to the actual damage done by the beetle the holes afford entrance to fungus spores, &c. Under the name " horn worms " are included the larvae or caterpillars of species of Protoparce.

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  • In cannel coals the prevailing constituents are the spores of cryptogamic plants, algae being rare or in many cases absent.

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  • In addition, the great majority have also another method of reproduction, for increasing the number of the parasites in any individual host; this is distinguished as multiplicative or endogenous reproduction, from the propagative or exogenous method (by means of the resistant spores), which serves for the infection of fresh hosts and secures the dissemination and survival of the species.

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  • The spores formed on the delicate grey mould are carried during the summer from one plant to another, thus spreading the disease, and also germinate in the soil where the fungus may remain passive during the winter producing a new crop of spores next spring, or sometimes attacking the scales of the bulbs forming small black hard bodies embedded in the flesh.

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  • This prevents infection from outside and also destroys any spores or fungus mycelium that may have been packed away along with the bulbs.

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  • Only a single pathogenic species can withstand the short boiling to which milk is ordinarily treated in domestic management, and this is the anthrax bacillus containing spores.

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  • mesentericus do not develop below 15° C.; but if it be introduced into the alimentary canal of a child the spores will rapidly multiply, and in such cases large quantities of gas, giving rise to flatulency, will be formed, and possibly also poisonous decomposition products of albuminoid matter.

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  • The spores germinate on a damp surface and enter the cortex through small cracks or wounds in the protecting layer.

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  • The algal cells are never known to form spores while part of the lichen-thallus, but they may do so when separated from it and growing free.

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  • There are three methods of reproduction of the lichen: by fragmentation, by soredia, by the formation of fungal spores.

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  • The soredia are the most successful method of reproduction in lichens, for not only are some forms nearly always without spore-formation and in others the spores laregly abortive, but in all cases the spore represents only the fungal component of the thallus, and its success in the development of a new lichen-thallus depends on the chance meeting, at the time of germination, with the appropriate algal component.

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  • The spores themselves may be unicellular without a septum or multicellular with one or more septa.

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  • At other times the spores are divided by both transverse and longitudinal septa producing the muriform (murali-divided) spore so called from the resemblance of the individual chambers to the stones in a wall.

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  • The very large single spores of Pertusaria have been shown to contain numerous nuclei and when they germinate develop a large number of germ tubes.

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  • The spores are ejected from the apothecia and peri thecia as in the fungi by forcible ejacu lation from the asci.

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  • the more important part in lichen distribution as the development of the r1012444 ordinary spores is dependent on their ?,O.° finding the proper alga on the sub- I t.?

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  • - In a number of forms (Endocarpon pusillum, Stigmaatonima cataleptum, various species of Staurothele), however, there is a special arrangement by which the spores are, on ejection, associated with gonidia.

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  • When the spores are thrown out some of these hymenial gonidia, as they are called, are carried with them.

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  • When the spores germinate the germ-tubes surround the algal cells, which now increase in size and become the normal gonidia of the thallus.

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  • b, Asci (thecae) with bilocular spores.

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  • A solution of iodine is also used as a test owing to the blue or wine-red colour which the thallus, hymenium or spores may give with this reagent.

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  • The paraphyses branch and form a network (capillitium) over the asci, the capillitium and ejected spores forming a long persistent powdery mass (mazaedium).

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  • Spores usually two-celled, either with a strongly thickened cross-wall often perforated by a narrow canal or with crosswall only slightly thickened.

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  • In the first case the spores are usually colourless, the second case always brown.

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  • Spores unicellular, parallel-multicellular or muriform, usually colourless, cross-walls usually thin.

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  • - These popular plants are usually increased by means of their spores, the " dust " produced on the back of their fronds.

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  • The spores should be sown in well-drained pots or seed pans on the surface of a mixture of fibrous sifted peat and small broken crocks or sandstone; this soil should be firmly pressed and well-watered, and the spores scattered over it, and at once covered with propagating glasses or pieces of sheet glass, to prevent water or dry air getting to the surface.

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  • The spores may be sown as soon as ripe, and when the young plants can be handled, or rather can be lifted with the end of a pointed flat stick, they should be pricked out into well-drained pots or pans filled with similar soil and should be kept moist and shady.

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  • Spores may be sown as above described, but in a much lower temperature.

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  • The reproductive spores are borne in sacs (asci) which form a dense layer on the surface, appearing like a bloom in July; they are scattered by the wind and propagate the disease.

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  • The reproductive spores are formed in embedded flesh-shaped receptacles (perithecia) and scattered after the leaves have fallen.

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  • fungus, a mushroom), the botanical name covering in the broad sense all the lower cellular Cryptogams devoid of chlorophyll, which arise from spores, and the thallus of which is either unicellular or composed of branched or unbranched tubes or cell-filaments (hyphae) with apical growth, or of more or less complex wefted sheets or tissue-like masses of such (mycelium).

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  • The spores, which may be unior multi-cellular, are either abstricted free from the ends of hyphae (acrogenous), or formed from segments in their course (chlamydospores) or from protoplasm in their interior (endogenous).

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  • It was formerly the custom to include with the Fungi the Schizomycetes or Bacteria, and the Myxomycetes or Mycetozoa; but the peculiar mode of growth and division, the cilia, spores and other peculiarities of the former, and the emission of naked amoeboid masses of protoplasm, which creep and fuse to streaming plasmodia, with special modes of nutrition and spore-formation of the latter, have led to their separation as groups of organisms independent of the true Fungi.

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  • As with other plants, so in fungi the essential process of fertilization consists in the fusion of two nuclei, but owing to the absence of well-marked sexual organs from many fungi, a peculiar interest attaches to certain nuclear fusions in the vegetative cells or in young spores of many forms. Thus in Ustilagineae the chlamydospores, and in Uredineae the teleutospores, each contain two nuclei when young, which fuse as the spores mature.

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  • Morphologically considered, spores are marked by peculiarities of form, size, colour, place of origin, definiteness in number, mode of preparation, and so forth, such that they can be distinguished more or less sharply from the hyphae which produce them.

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  • The only physiological peculiarity exhibited in common by all spores is that they germinate and initiate the production of a new fungus-plant.

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  • Whether a spore results from the sexual union of two similar gametes (zygospore) or from the fertilization of an egg-cell by the protoplasm of a male organ (oospore); or is developed asexually as a motile (zoospore) or a quiescent body cut off from a hypha (conidium) or developed along its course (oidium or chlamydospore), or in its protoplasm (endospore), are matters of importance which have their uses in the classification and terminology of spores, though in many respects they are largely of academic interest.

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  • Klebs has attemped to divide spores into three categories as follows: (I) kinospores, arising by relatively simple cell-divisions and subserving rapid dissemination and propagation, e.g.

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  • In practice these various kinds of spores of fungi receive further special names in the separate groups, and names, more over, which will appear, to those unacquainted with the history, to have been given without any consistency or regard to general principles; nevertheless, for ordi nary purposes these names are far more useful in most cases, owing to their descriptive character, than the proposed new names, which have been only partially accepted.

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  • c, Conidium emitting zooC. Formation of zoospores by spores.

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  • Other series of modifications arise in which the tissues corresponding to the stroma invest the sporogenous hyphal ends, and thus enclose the spores, asci, basidia, &c., in a cavity.

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  • Another simple case is where the plane or slightly convex surface of the stroma rises at its margins and overgrows the sporogenous hyphal ends, so that the spores, asci, &c., come to lie in the depression of a cavity - e.g.

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  • In such examples as the above we may regard the hymenium (Solenia, Cyphella), zygospores, or asci as truly invested by later growth, but in the vast majority of cases the processes which result in the enclosure of the spores, asci, &c., in a "fructification" are much more involved, inasmuch as the latter is developed in the interior of hyphal tissues, which are by no means obviously homologous with a stroma.

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  • Then a hollow appears in the centre owing to the more rapid extension of the outer parts, and into this hollow the cells lining it put forth short sporogenous branches, from the tips of which the spores (stylospores, c nidia, spermatia) are abstricted.

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  • The outer parts of the mass then differentiate as a wall or investment, and the interior becomes a hollow, into which hyphal ends grow and abstrict the spores.

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  • - Ordinary conidia and similarly abstricted dry spores are so minute, light and numerous that their dispersal is ensured by any current of air or water, and we also know that rats and other burrowing animals often carry them on their fur; similarly with birds, insects, slugs, worms, &c., on claws, feathers, proboscides, &c., or merely adherent to the slimy body.

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  • A more complicated case is illustrated by Sphaerobolus, where the entire mass of spores, enclosed in its own peridium, is suddenly shot up into the air like a bomb from a mortar by the elastic retroversion of a peculiar layer which, up to the last moment, surrounded the bomb, and then suddenly splits above, turns inside out, and drives the former as a projectile from a gun.

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  • Such gums are formed abundantly in pycnidia, and, absorbing water, swell and carry out the spores in long tendrils, which emerge for days and dry as they reach the air, the glued spores gradually being set free by rain, wind, &c. In oidial chains (Sclerotinia) a minute double wedge of wall-substance arises in the middle lamella between each pair of contiguous oidia, and by its enlargement splits the separating lamella.

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  • These disjunctors serve as points of application for the elastic push of the swelling spore-ends, and as the connecting outer lamella of cell-wall suddenly gives way, the spores are jerked asunder.

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  • In many cases the slimy masses of spermatia (Uredineae), conidia (Claviceps), basidiospores (Phallus, Coprinus), &c., emit more or less powerful odours, which attract flies or other insects, and it has been shown that bees carry the flagrant oidia of Sclerotinia to the stigma of Vaccinium and infect it, and that flies carry away the foetid spores of Phallus, just as pollen is dispersed by such insects.

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  • Whether the strong odour of trimethylamine evolved by the spores of Tilletia attracts insects is not known.

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  • Thallus septate; spores developed in special type of sporangium, the ascus, the number of spores being usually eight.

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  • The development of the "conidia" as true conidial spores or as zoosporangia may occur in one and the same species (Cystopus candidus, Phytophthora infestans) as in Pythium described above; in other cases the direct conidial germination is characteristic of genera - e.g.

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  • In some cases resting spores are formed inside the host (Chytridium), and give rise to zoosporangia on germination.

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  • They are characterized especially by the zygospores, but the asexual organs (sporangia) exhibit interesting series of changes, beginning with the typical sporangium of Mucor containing numerous endospores, passing to cases where, as in Thamnidium, these are accompanied with more numerous small sporangia (sporangioles) containing few spores, and thence to Chaetocladium and Piptocephalis, where the sporangioles form but one spore and fall and germinate as a whole; that is to say, the monosporous sporangium has become a conidium, and Brefeld regarded these and similar series of changes as explaining the relation of ascus to conidium in higher fungi.

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  • According to his view, the ascus is in effect the sporangium with several spores, the conidium the sporangiole with but one spore, and that not loose but fused with the sporangiole wall.

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  • In addition to sporangia and the conidial spores referred to, some Mucorini show a peculiar mode of vegetative reproduction by means of gemmae or chlamydospores - i.e.

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  • short segments of the hyphae become stored with fatty reserves and act as spores.

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  • These then become surrounded by a cell-wall and form the spores.

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  • These structures cannot 3, then be produced from the product of a single spore nor even from the thalli derived from any two spores.

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  • They are remarkable for their dark spores developed in gall-like excrescences on the leaves, stems, &c., or in the fruits of the host.

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  • The discovery of the yeast-conidia of these fungi, and their thorough investigation by Brefeld, have thrown new lights on the group, as also have the results elucidating the nature of the ordinary dark spores - smuts, bunt, &c. - which by their mode of origin and development are chlamydospores.

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  • Brefeld regarded the promycelium as a kind of basidium, bearing lateral or terminal conidia (comparable to basidiospores), but since the number of basidiospores is not fixed, and the basidium has not yet assumed very definite morphological characters, Brefeld termed the group Hemibasidii, and regarded them as a halfway stage in the evolution of the true Basidiomycetes from Ph co Y Y mycetes, the Tilletia type leading to the true basidium (Autobasidium), the Ustilago type to the proto pm basidium, with lateral spores; but this p m view is based on very poor evidence, so that it is best to place these forms?p, c;,::, as a separate group, the Ustilaginales.

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  • In some cases nuclear division is carried further before spore-formation occurs, and the number of spores is then 16, 32 and 64, &c.; in a few cases the number of spores is less than eight by abortion of some of the eight nuclei.

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  • (After Harper.) Young ascus of Boudiera with eight spores.

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  • (After Claussen.) D, spores.

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  • The sporangium with its endogenous spores has been compared with an ascus, and on these grounds the group is placed among the Ascomycetes - a very doubtful association.

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  • Under other conditions, of which the temperature is an important one, the nucleus in the yeast-cell divides, and each daughter-nucleus again, and four spores are formed in the mother cell, a process obviously comparable to the typical development of ascospores in an ascus.

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  • The fused cell becomes a sporangium, and in it eight spores are developed.

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  • In certain cases single cells develop parthenogenetically, without fusion, each cell producing, however, only four spores.

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  • In the formation of spores the nucleus of the cell divides, the protoplasm collects round the nuclei to form the spores by free-cell formation; the protoplasm (epiplasm) not used in this process becomes disorganized.

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  • If there are two fusions one would expect two reductions, and Harper has suggested that the division of the nuclei into eight in the ascus, instead of into four spores as in most reduction processes, is associated with a double reduction process in the ascus.

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  • Four ripe asci, a i, a2, with eight spores, a 3, a4, with yeast-like conidia abstricted from the spores.

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  • The asci are developed in the large dense fruit bodies (cleistothecia) and the spores escape by the decay of the wall.

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  • Owing to the presence of oily globules of an orange-yellow or rusty-red colour in their hyphae and spores they are termed Rust-Fungi.

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  • They are distinguished from the other fungi and the rest of the Basidiales by the great variety of the spores and the great elaboration of the life-history to be found in many cases.

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  • Whether B, Formation of the first sporethe association of nuclei in the mother-cell (sm), from the ordinary mycelium takes place basal cell (a) of one of the by the migration of a nucleus rows of spores.

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  • In Dacryomyces only two outgrowths and two spores are produced.

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  • In these sporophores (such as the well-known toadstools and mushrooms where the ordinary vegetative mycelium is underground) we have structures specially developed for bearing the basidiospores and protecting them from rain, &c., and for the distribution of the spores - see earlier part of article on distribution of spores (figs.

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  • fruit-bodies which only open after the spores are ripe and then often merely by a small pore.

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  • By the breaking down of the inner tissues the spores often come to lie as a loose powdery mass in the interior of the hollow fruitbody, mixed sometimes with a capillitium.

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  • Spore Distribution: Fulton, "Dispersal of the Spores of Fungi by Insects," Ann.

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  • Spores and Sporophores: Zopf, Die Pilze; also the works of von Tafel and Brefeld.

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  • The development of the microsporangia and the contained spores (pollen -grains) P (P g is closely comparable with that of the microsporangia in Gymnosperms or heterosporous ferns.

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  • The mature pollengrain is, like other spores, a single cell; except in the case of some submerged aquatic plants, it has a double wall, a thin delicate wall of unaltered cellulose, the endospore or intine, and a tough outer cuticularized exospore or extine.

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  • The number of chromosomes in the nucleus of the two spores, pollen-grain and embryo-sac, is only half the number found in an ordinary vegetative nucleus.

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  • The full number is restored in the fusion of the male and female nuclei in the process of fertilization, and remains until the formation of the cells from which the spores are derived in the new generation.

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  • Here the contents of certain cells break up endogenously into a great number of spores, which are distributed as a fine dust.

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  • Resting spores are also known.

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  • The asexual cells are immotile spores arising in fours in sporangia from superficial cells of the thallus.

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  • The spores of Monospora are by some regarded as unicellular propagula.

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  • Thus in Lemaneaceae asexual spores are unknown; in Batracho-spermum, Bonnemaisonia and Polysiphonia byssoides both kinds of sexual cells appear on the same plant; and in some cases the asexual cells may occur in conjunction with either the male or female sexual cells.

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  • The tetraspores may arise by the simultaneous division of the contents of a sporangium, when they are arranged tetrahedrally, or they may arise by two successive divisions, in which case the arrangement may be zonate when the spores are in a row, or cruciate when the second divisions are at right angles to the first, or tetrahedral when the second divisions are at right angles to the first and also to one another.

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  • Polysiphonia sp., transverse section through a branch, and at spores arising from fertilized carpogonium.

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  • Callithamnion sp., tetrasporangium with spores arranged in a and a, b, two auxiliary cells.

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  • spores.

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  • There is here obviously a certain parallelism with the case of Bryophyta, where the sporogonium arising from the oospore is epiphytic and partially parasitic upon the female plant, and always culminates in the production of spores.

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  • It is possible, however, that the tetraspore formation should be regarded as comparable with the prolific vegetative reproduction of Bryophyta, and in favour of this view there is the fact that the tetraspores originate on the thallus in a different way from carpospores with which the spores of Bryophyta are in the first place to be compared; moreover, in certain Nemalionales the production of tetraspores does not occur, and the difficulty referred to does not arise in such cases.

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  • ..Bangiaceae - Eti Florideae Eugleneae Chi Iromonadinae Pleurococcaceae - Endosphaeraceae Volvocaceae hlorosphaeraceae � CoNJuGA'rAE, Siphonales Tetrasporaceao Ulvaceae Confdyvaleb Characeae in the culminating stage of Fucus, where the oogonium is separated from the stalk-cell, so that unless it be contended that the Fucus is really a sporophyte which does not produce spores, and that the gametophyte is represented merely by the oogonium and antheridium, there is no semblance of alternation of generation in this case.

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  • The spores of the Aglaozonia form are known to give rise to sexual plants, and the oospore of Cutleria has been observed to grow into rudimentary Aglaozonia.

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  • "Dry rot," which usually attacks the sap-wood, generally starts in a warm damp unventilated place, and is caused by the growth of fungi, some of which are visible to the naked eye, some microscopic. The spores from the fungi on the decayed wood float in the air and alight on any adjacent timber, infecting this also if the conditions be favourable.

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  • The spores of the fungus will find a way through brickwork, concrete and similar material, in order to reach woodwork that may be on the other side.

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  • On the destruction of the leaves the fungus either descends the stem by the interior or the spores are washed by the rain to the tubers in the ground.

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  • In either case the tubers are reached by the fungus or its spores, and so become diseased.

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  • The germinating spores are not only able to pierce the leaves and stems of the potato plant, and so gain an entry to its interior through the epidermis, but they are also able to pierce the skin of the tuber, especially in young examples.

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  • It is therefore obvious that, if the tubers are exposed to the air where they are liable to become slightly cracked by the sun, wind, hail and rain, and injured by small animals and insects, the spores from the leaves will drop on to the tubers, quickly germinate upon the slightly injured places, and cause the potatoes to become diseased.

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  • The last measure prevents the germination of the spores of the fungus on the leaves, and is a most useful mode of checking the spread of the disease; to be successful in its use, however, entails care in the preparation of the spray and thoroughness in its application.

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  • It is characterized by the curling of the leaves, which later show black A spots due to the production of numerous dark spores in patches on the diseased leaves.

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  • 3, Section through diseased tissue showing dark masses of spores.

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  • 4 and 5, Tissue-cell, more highly magnified, showing enclosed spores.

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  • The spores of the fungus pass the winter in the soil and the delicate mycelium attacks the young shoots in the summer.

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  • The first signs of this fungus is the appearance of small white tufts of mycelium bursting through the skin of the tuber, the spores of the fungus being carried at the tips of the threads forming these tufts.

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  • The pieces of dried-up potato with the spores of Nectria upon them are a source of infection in the succeeding year, and care should be taken that diseased tubers are not planted.

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  • The fact that Schizomycetes produce spores appears to have been discovered by Cohn in 1857, though it was expressed dubiously in 1872; these spores had no doubt been observed previously.

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  • In 1876, however, Cohn had seen the spores germinate, and Koch, Brefeld, Pratzmowski, van Tieghem, de Bary and others confirmed the discovery in various species.

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  • No case' of so-called " spontaneous generation " has withstood rigid investigation; but the discussion contributed to more exact ideas as to the ubiquity, minuteness, and high powers of resistance to physical agents of the spores of Schizomycetes, and led to more exact ideas of antiseptic treatments.

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  • Koch in 1876 published his observations on Davaine's bacilli, placed beyond doubt their causal relation to splenic fever, discovered the spores and the saprophytic phase in the life-history of the organism, and cleared up important points in the whole question (figs.

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  • - The various phases of germination of spores of Bacillus ramosus (Fraenkel), as actually observed in hanging drops under very high powers.

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  • Germinating spores in various stages, more highly magnified, and showing the different ways of escape of the filament from the spore-membrane.

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  • Various stages in the development of the endogenous spores in a Clostridium - the small letters indicate the order.

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  • Endogenous spores of the hay bacillus.

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  • C. A chair of cocci of Leuconostoc mesenterioides, with two " resting spores," i.e.

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  • Clostridium - one cell contains two spores.

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  • Spirillum containing many spores (a), which are liberated at b by the breaking up of the parent cells.

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  • c, d, e, f, successive stages in the development of the spores.

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  • g ', g 2, g3, early stages in the germination of the spores (after being dried several days); h2, i, k, 1 and m, successive stages in the germination of the spore.

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  • The rodlets after three hours' culture in a drop of aqueous become septate later, and spores are developed in the segments.

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  • W.) A very characteristic method of reproduction is that of sporeformation, and these minute reproductive bodies, which represent a resting stage of the organism, are now known in many spores.

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  • forms. Formerly two kinds of spores were described, arthrospores and endospores.

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  • The germination of the spores has now been observed in several forms with care.

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  • A The spores are capable of germination at once, or they may be kept for months and even years, and are very resistant against desiccation, heat and cold, &c. In a suitable medium and at a proper temperature the germination is completed in a few hours.

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  • The systematic interference with these conditions has enabled bacteriologists to induce the development of socalled asporogenous races, in which the formation of spores is indefinitely postponed, changes in vigour, virulence and other properties being also involved, in some cases at any rate.

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  • C. Development of spores (X 800).

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  • Systems have also been brought forward based on the formation of arthrospores and endospores, but as explained above this is eminently unsatisfactory, as arthrospores are not true spores and both kinds of reproductive bodies are found in one and the same form.

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  • - Stages in the development of spores of Bacillus ramosus (Fraenkel), in the order and at the times given, in a hanging drop culture, under a very high power.

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  • The process begins with the formation of brilliant granules (A, B); these increase, and the brilliant substance gradually balls together (C) and forms the spores (D), one in each segment, which soon acquire a membrane and ripen (E).

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  • io), in which spores are being developed.

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  • The specimen was cultivated in broth, and spores are drawn a little too small - they should be of the same diameter transversely as the segments.

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  • (After de Bary.) "1, fragments of filaments with ripe spores; 2-5, successive stages in the germination of the spores, the remains of the spore attached to the germinal rodlets.

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  • W.) which Arloing, Buchner, Chmelewski, and others took part, have led to the proof that rays of light alone are quite capable of killing these organisms. The principal questions were satisfactorily settled by Marshall Ward's experiments in 1892-1893, when he showed that even the spores of B.

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  • Even when the light is not sufficiently intense, or the exposure is too short to kill the spores, the experiments show that attenuation of virulence, That bacterial fermentations are accompanied by the evolution of heat is an old experience; but the discovery that the " spontaneous " combustion of sterilized cotton-waste does not occur simply if moist and freely exposed to oxygen, philous bacteria.

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  • Apart from the resolution of doubts as to the power of spores to withstand such temperatures for long periods, the discoveries of Miguel, Globig and others have shown that there are numerous bacteria which will grow and divide at such temperatures, e.g.

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  • The somewhat different question of the resistance of ripe spores or cells to extremes of heat and cold has received attention.

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  • It is probable that all these cases of resistance of seeds, spores, &c., are to be connected with the fact that completely dry albumin does not lose its coagulability on heating to I Io° C. for some hours, since it is well known that completely ripe spores and dry heat are the conditions of extreme experiments.

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  • fermentations induced by them, the resistance of their spores to dessication, heat, &c. - but it is worth while to ask how far these properties are really remarkable when all the data for comparison with other organisms are considered.

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  • Spores, &c.: Marshall Ward, " On the Biology of B.

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  • The sporangial wall, consisting of several layers of cells, encloses a cavity containing numerous oval spores (pollen-grains).

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  • In structure a cycadean sporangium recalls those of certain ferns (Marattiaceae, Osmundaceae and Schizaeaceae), but in the development of the spores there are certain peculiarities not met with among the Vascular Cryptogams. With the exception of Cycas, the female flowers are also in the form of cones, bearing numerous carpellary scales.

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  • It is therefore natural that attempts should have been made to construct filters which, while permitting the slow percolation of water, should preclude the passage of bacteria or their spores.

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  • Subjection to the temperature of boiling water for, say, half an hour seemed an efficient mode of sterilization, until it was discovered that the spores of bacteria are so involved in heat-resisting membranes, that only prolonged exposure to dry, baking heat can be recognized as an efficient process of sterilization.

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  • Moreover, the presence of bacteria, or their spores, is so universal that only extreme precautions guard against a re-infection of the sterilized material.

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  • The cells of the wall of the sporangium are usually so constructed as to determine the dehiscence of the sporangium and the liberation of its spores.

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  • The spores produced in each sporangium vary from very many to a single one in the case of some heterosporous forms. These latter bear spores of two kinds, microspores and megaspores, in separate sporangia.

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  • The spores of the homosporous Vascular Cryptogams are usually of small size; the prothalli produced from them usually bear both antheridia and archegonia, though under special conditions an imperfect sexual differentiation may result.

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  • On the formation of the spores a reduction to the number characteristic of the gametophyte takes place.

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  • The latter arises from a number of superficial cells, the cells destined to form the spores being derived from a single one of these.

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  • A tapetal layer is derived from the cells surrounding the sporogenous group, and the arrest of a number of the spore-mother-cells further contributes to the nourishment of the remainder, each of which gives rise to four spores.

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  • Further, several spores will be likely to germinate together owing to their elaters becoming entangled; a fact of some importance, since the antheridia and archegonia, though occurring sometimes on the same prothallus, are more often borne on separate individuals.

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  • The spores are formed in sporangia of considerable size, situated on the upper surface and near the base of the sporophylls.

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  • The spores, when liberated by the dehiscence of the sporangium, give rise to the prothallus, which is now, owing mainly to the investigations of Treub and Bruchmann, known in a number of tropical and temperate species.

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  • The cells composing the young sporangium are at first similar, but ultimately become differentiated into sterile trabeculae, which may stretch from the inner to the outer wall, and the mother-cells of the spores.

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  • The spores, which are set free by the rotting of the sporangial wall, germinate much as in the case of Selaginella, though the similarity may be a case of independent resemblance.

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  • The spores produce a green prothallus of large size, the sexual organs of which hardly project from the surface.

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  • When mature, the sporangia are raised above the margin of the indusium by the elongation of the receptacle, thus facilitating the dispersion of the spores.

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  • A consideration of the biology of the sorus gives an insight into the advantages obtained by the one type over the preceding, as regards protection, spore production and the dispersal of the spores, and thus indicates the way in which natural selection may have acted.

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  • Each sorus includes both microsporangia, with numerous spores, and megasporangia, each of which contains a single megaspore with a complicated wall.

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  • Enclosed within the sporocarp they can endure a period of drought, but on the return of moist conditions are extruded from the sporocarp by the swelling of a special mucilaginous tissue and the spores become free.

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  • It may be regarded as derived from a wholly dependent sporogonium not unlike that of some of the simpler Bryophyta; the latter are assumed to have arisen from primitive Algal forms, in which, as the first step in the interpolation of the second generation in the life cycle, the fertilized ovum gave rise to a group of swarm spores, each of which developed into a new sexual plant.

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  • While a number of ferns can be multiplied vegetatively, by buds formed on the leaves and in other ways, the regular mode of propagation is by sowing the spores shed from the ripe sporangia.

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  • The spores should be thinly sprinkled on the surface of the soil in well-drained pots, which should stand in saucers filled with water and be covered with glass plates.

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  • These coloured spots are due to the presence of a sorus or layer of countless numbers of minute brown spores, the uredospores of the summer fruiting form.

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  • The spores, when mature, are easily detached, and are carried by insects or by the wind to other wheat-plants.

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  • Wind dispersal of the spores would account for mysterious appearances of the disease, in some years almost every straw in a wheat-field being affected, while in other years scarcely one is attacked.

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  • Fungus spores will not germinate without moisture, and attention to drainage helps to keep down this and other fungus pests.

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  • The developing seed thus encloses fungal hyphae, which remain dormant within the seed and in spring develop symbiotically with the growth of the wheat plant, doing no apparent injury until the time of fruiting is reached, when the fungus takes complete possession and fills the new seed with a mass of darkcoloured spores.

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  • It is impossible to detect the first infection or to cleanse the seed; the only remedy is to procure seed from a smut-free source, and to prevent further spread of the disease by gathering all smutted heads before the spores have matured or dispersed.

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  • The spores of the fungus remain in the soil or in manure-heaps until spring, when they germinate and attack the first green leaves of the host plant.

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  • The after development is similar to that of smut, and the seed grain becomes a mere mass of fungus spores.

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  • Much can be done in this case to clean the seed before sowing by immersing it in hot water or in some solution that will kill the spores without injuring the grain.

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  • The danger of contagion lies in the wonderful vitality of the spores, and their great resistance to heat and cold.

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  • Dr Maassen records a case where he had no difficulty in obtaining cultures from spores removed from combs after being kept dry for twenty years.

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  • It should be " a place for everything and everything in its place " prepares the bee-keeper for any emergency; constant watchfulness is also necessary, not only to guard against disease in needs a reminder of this truism he surely has it in the borne in mind that the disease is much easier to cure in the earlier stages while the bacilli are still rod-shaped than when the rods have turned to spores.

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  • These are with few exceptions foliar structures, known in comparative morphology as sporophylls, because they bear the spores, namely, the microspores or pollen-grains which are developed in the microsporangia or pollen-sacs, and the megaspore, which is contained in the ovule or megasporangium.

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  • If sporangia and spores are present they also may persist in a perfectly recognizable form, and in fact much of our knowledge of the fructification of fossil Ferns and similar plants has been derived from specimens of this kind.

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  • Here it need only be said that the masses of vegetable substance, more or less carbonized and chemically altered, of which coal is composed, frequently contain cells and fragments of tissue in a condition recognizable under the microscope, as for example spores (sometimes present in great quantities), elements of the wood, fibres of the bark, &c. These remnants, however, though interesting as revealing something of the sources of coal, are too fragmentary and imperfect to be of any botanical importance.

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  • Conceptacles contaning Spores, and strongly suggesting the Chytridineous Fungus Urophlyetis, have recently been found, in petrified material, on the leaves of an Alethopteris, which appears to have undergone decay before fossilization set in.

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  • Small spores, almost certainly those of Fungi, are very common in the petrified tissues of Palaeozoic plants.

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  • The spores are frequently found to be still united in tetrads.

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  • The abortion of certain spores, which is known to have taken place both in the homosporcus C. Binneyana and in the megasporangia of C. Casheana, may throw some light on the origin of the heterosporous condition.

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  • Dehiscence appears to have taken place at the free end of the sporangium; the spores are numerous, and, so far as observed, of one kind only.

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  • and contain either an im The upper sporangia contain numermense number of minute ous microspores; in each of the lower spores or a very small number sporangia four megaspores are shown.

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  • of exceedingly large spores (fig.

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  • The spores of this genus are curiously winged, and intermediate in size between the microspores and megaspores of Lepidostrobus; the question of homospory or heterospory is not yet decided.

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  • Each sporangium had, on one side only, a longitudinal or slightly oblique annulus, several cells in width; the numerous spores were all of the same size; certain differences among them, which have been interpreted as indicating heterospory, have now proved to depend merely on the state of preservation.

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  • Four germinating spores from the interior of a sporangium.

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  • airborne spores are released which infect susceptible plants.

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  • anthrax spores left in the ground retain their viability?

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  • These apothecia produce ascospores - the sexual spores of the fungus.

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  • Fungi with spores produced inside a sac called an ascus.

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  • asexual spores 10 to 60 minutes later.

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  • bacillus anthracis to form spores makes it a difficult organism to control.

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  • It is advisable to place the leather in clean polythene bags rather than reusing the original packaging which may harbor fungal spores.

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  • biocidal activity with efficacy with efficacy against spores, bacterial, fungal and viral organisms.

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  • conidiumer to disperse themselves widely they produce spores called conidia.

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  • crawl around in the slime, becoming covered in spores.

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  • dispersal of disease spores like those of black spot (Colletotrichum acutatum) is reduced by straw mulch.

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  • disperse the spores when they leave and go elsewhere.

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  • fern spores, they would become invisible.

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  • In other areas mudstones have been found with microfossil plant spores and one of the later sandstones near Cheadle has fossil footprints of reptiles.

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  • frosty pod is the hardier species, with spores that can travel further in hot, dry conditions.

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  • fungal spores at most times of the year.

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  • germinatedies of the life cycle of the rust fungus convinced him that the germinating spores represented a vulnerable stage for attack.

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  • Histoplasma duboisii Vanbreuseghem) The spores of these organisms can cause the lung disease histoplasmosis if inhaled (Roberts et al.

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  • Anthrax in Plaster Plaster usually contains horsehair and, before controls were introduced in 1895, could contain anthrax spores.

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  • Spores carried in the air land on dead or dying trees and produce hyphae which ramify through the wood.

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  • It takes only a few days for mold spores to germinate, and only a few weeks to extend hyphae and grow extensively.

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  • inhalation of anthrax spores is potentially the most serious route of infection.

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  • Dugway is also the only facility known in recent years to have processed anthrax spores into the powdery form that is most easily inhaled.

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  • lycopodium spores were employed in all cases, 2kg. per sink.

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  • Spores are usually microscopic, and are produced in a variety of ways.

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  • This mixture will kill any mold or mold spores that may not be visible.

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  • mouldnging green wood indoors to dry can promote the growth of allergy-causing mold spores circulating indoors.

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  • multiplyected animals it multiplies in the gut, forming tiny spores called oocysts, which are excreted in feces in very large numbers.

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  • Do not feed foreign honey or honey of unknown origin, which may contain AFB spores.

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  • Sporangia Sporangia are the airborne spores of the blight pathogen and are responsible for the rapid spread of the disease in crops.

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  • peristome teeth contract, opening up a gap, the wind can shake the spores out of the capsule.

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  • The spores are released through pores are released through pores on the underside.

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  • Such spores can rapidly spread down the soil profile in field conditions.

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  • reproducert - a small flowerless green plant with leaf-like stems or lobed leaves, lacking true roots and reproducing by spores.

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  • resting spores of microorganisms are carried with the wind.

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  • B, spores germinate away from a living root hair (rh ).

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  • rust spores require water for germination.

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  • Spores are tardily septate, with 7 or more septa, irregularly spaced.

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  • The head is covered in foul-smelling slime, which contains the spores.

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  • sporangiumerent types of asexual ' spores ' called sporangia and chlamydospores are formed.

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  • His studies of the life cycle of the rust fungus convinced him that the germinating spores represented a vulnerable stage for attack.

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  • In 2000 a Dutch woman in her 20s died from Pigeon Lung disease caused by inhaling spores from droppings.

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  • These cells are sensitive to slight changes in humidity, causing a twisting action that aids in dispersing the spores.

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  • The air is also full of fungal spores at most times of the year.

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  • Fruiting bodies take 4 to 6 hours to develop and they can start releasing asexual spores 10 to 60 minutes later.

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  • In spring airborne spores are released which infect susceptible plants.

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  • Many resting spores of microorganisms are carried with the wind.

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  • Differentiation - bacterial spores are one of the most resistant life forms on earth.

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  • When the foliage dries more quickly, infections are reduced since, like almost all fungal spores, rust spores require water for germination.

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  • How long might anthrax spores left in the ground retain their viability?

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  • This mixture will kill any mold or mold spores that may not be visible.

    0
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  • The harmful effects of mold spores cannot surface in the finished oil.

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  • However, putting a culture containing millions of bacillus anthracis spores into a form that makes an effective weapon is not easy.

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  • People used to believe that if a person carried fern spores, they would become invisible.

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  • It will also destroy fungi spores giving freedom from rust.

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  • spores of the fungi are sprayed on the crop pests.

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  • spores per ml were required to ensure a good amount of growth.

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  • The plant producing the spores is called the sporophyte.

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  • When these spores germinate they must find a suitable photosynthetic partner in order to re-establish the lichen symbiosis.

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  • Rain then washes spores from the leaves down into the soil where they can infect the tubers.

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  • underside of the fronds tiny structures develop - containing the spores which will eventually produce new plants.

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  • When conditions of moisture, temperature, and food supply became unfavorable, many soil bacteria would form resistant spores.

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  • unknown origin, which may contain AFB spores.

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  • viable micro-organisms, including bacterial spores.

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  • wind-borne asexual spores and the dormant phase is as mycelium in dead leaf matter during frosty or dry summer conditions.

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  • Eventually, the resting spores germinate to release haploid zoospores which repeat the infection cycle. [© Jim Deacon] Fig.

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  • In most cases four spores are formed within the cell by free formation.

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  • The formation of spores in yeast (first discovered by T.

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  • The formation of spores is used as an analytical method for determining whether a yeast is contaminated with another species, - for example: a sample of yeast is placed on a gypsum or porcelain block saturated with water; if in ten days at a temperature of 52° F.

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  • no spores make their appearance, the yeast in question may be regarded as S.

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  • To summarize the characters of a true mushroom - it grows only in pastures; it is of small size, dry, and with unchangeable flesh; the cap has a frill; the gills are free from the stem, the spores brown-black or deep purple-black in colour, and the stem solid or slightly pithy.

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  • When a mushroom is perfectly ripe and the gills are brown-black in colour, they throw down a thick dusty deposit of fine brown-black or purple-black spores; it is essential to note the colour.

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  • The spores on germination make a white felted mat, more or less dense, of mycelium; this, when compacted with dry, half-decomposed dung, is the mushroom spawn of gardeners.

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  • The true mushroom itself is to a great extent a dung-borne species, therefore mushroom-beds are always liable to an invasion from other dung-borne forms. The spores of all fungi are constantly floating about in the air, and when the spores of dung-infesting species alight on a mushroom-bed they find a nidus already prepared that exactly suits them; and if the spawn of the new-comer becomes more profuse than that of the mushroom the stranger takes up his position at the expense of the mushroom.

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  • The common mushroom (Agaricus campestris) is propagated by spores, the fine black dust seen to be thrown off when a mature specimen is laid on white paper or a white dish; these give rise to what is known as the "spawn" or mycelium, which consists of whitish threads permeating dried dung or similar substances, and which, when planted in a proper medium, runs through the mass, and eventually develops the fructification known as the mushroom.

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  • emitted from all habitable worlds in the form of spores which traverse space for years or ages, the majority being ultimately destroyed by the heat of some blazing star, but some few finding a resting-place on bodies which have reached the habitable stage.

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  • E, Dry spores showing the ex F, Sterile vegetative shoot.

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  • The spores differ from those of ferns in their outer coat (exospore) being split up into four club-shaped hygroscopic threads (elaters) which are curled when moist, but become straightened when dry.

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  • The seeds of the cryptogams or flowerless plants are not true seeds and are properly designated "spores" (see Fruit).

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  • Similarly in Schizocladium portions of the hydrocaulus are cut off to form so-called " spores," which grow into new individuals (see Allman [1]).

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  • The plant world falls into two great divisions, the higher or flowering plants (Phanerogams), characterized by the formation of a seed, and the lower or flowerless plants (Cryptogams), in which no seed is formed but the plants are disseminated by means of unicellular bodies termed spores.

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  • The Archegoniatae are characterized by a well-marked alternation of gametophyte and sporophyte generations; the former bears the sexual organs which are of characteristic structure and known as antheridia (male) and archegonia (female) respectively; the fertilized egg-cell on germination gives rise to the spore-bearing generation, and the spores on germination give rise directly or indirectly to a second gametophyte.

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  • The spores, as in the heterosporous Pteridophyta, are of two kindsmicrospores (pollen grains) borne in microsporangia (pollen sacs) on special leaves (sporophylls) known as stamens, and macrospores (embryo-sac) borne in macrosporangia (ovules) on sporophylls known as carpels.

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  • The simpler Fungi, like the simpler Green Algae, consist of single cells or simple or branched cell-threads, but among the higher kinds a massive body is often formed, particuTissue t~Jf larly in con nexion with the formation of spores, and, er~n,~,onthiS may exhibit considerable tissue-differentiation.

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  • The sporogonium of the liverworts is in the simpler forms simply a spore-capstile with arrangements for the development, protection and distribution of the spores.

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  • ferns, horse-tails, club mosses, &c., and Phanerogams or Flowering Plants) the main plant-body, that which we speak of in ordinary language as the plant, is called the sporophyte because it bears the asexual reproductive cells or spores.

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  • Special wound-cork is also often formed round accidental injuries so as to prevent the rotting of the tissues by the soaking in of rain and the entrance of fungal spores and bacteria.

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  • For instance, a Fungus epidemic is impossible unless the climatic conditions are such as to favor the dispersal and germination of the spores; and when plants are killed off owi~ig to the supersaturation of the soil with water, it is by no means obvious whether the excess of water and dissolved materials, or the exclusion of oxygen from the root-hairs, or the lowering of the temperature, or the accumulation of foul products of decomposition should be put into the foreground.

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  • The spores of Rusts, Erysipheae an d other Fungi may be conveyed from plant to plant by snails; those of tree-killing polyporei, &c., by mice, rabbits, rats, &c., which rub their fur against the hymenophores.

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  • Bees carry the spores of Scierotinia as they do the pollen of the bilberries, and flies convey the conidia of ergot from grain to grain.

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  • Worms bring spores to the surface of soil, ducks and other birds convey them or their muddy feet.

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  • Gardeners and farm laborers convey spores from one bed or field to another; carted soil, manure, &c., may abound in spores of Smuts, Fusarium, Polyporei and in sclerotia; and articles through the post and so forth often carry infective spores.

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  • Erysiphe, or the steeping in hot water of thoroughly ripe hard grains to which spores are attached, e.g.

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  • those due to .Synchytrium, Protomyces, Cysto pus, many Ustilagineae, &c. These cases are not easily distinguished superficially froni the pustular outgrowth of actual mycelia and spores (stromata) of such Fungi as Nectria, Puccinia, &c. The cylindrical stem-swellings due to Calyptospora, Epichloe, &c., may also be mentioned here, and the tyro may easily confound with these the layers and cushions of eggs laid on similar organs by moths.

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  • In some cases both the nucleus and the chromatophores may be carried along in the rotating stream, but in others, such as T.Titeila, the chloroplasts may remain motionless iii a non-motile layer of the cytoplasm in direct contact with the cell wall.i Desmids, Diatoms and Oscillaria show creeping movements probably due to the secretion of slime by the cells; the swarmspores and plasmodium of the Myxomycetes exhibit amoehoid movements; and the motile spores of Fungi and Algae, the spermatozoids of mosses, ferns, &c., move by means of delicate prolongations, cilia or flagella cf the protoplast.

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  • In the Thallophytes the cytoplasm may be segmented by constriction, due to the in-growth of a new cell wall from the old one, as in Spirogyra and Cladophora, or by the formation of cleavage furrows in which the new cell-wall is secreted, as occurs in the formation of the spores in many Algae and Fungi.

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  • In a few cases both among the higher and the lower plants, of which the formation of spores in the ascus is a typical example, new cells are formed by the aggregation of portions of the cytoplasm around the nuclei which become delimited from the rest of the cell iontents by a membrane.

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  • many motile unicellular Algae and swarm spores is also probably concerned with the active response to light exhibited by these organisms. In Euglena viridis, which has been most carefully studied in this respect, the flagellum which brings about the movement bears near its base a minute spherical or oval refractive granule or swelling which is located just in the hollow of the red pigment-spot (fig.

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  • Accepting this view of the phylogeny of the leaf, the perianthleaves (sepals and petals) and the foliage-leaves may be regarded as modified or metamorphosed sporophylls; that is, as leaves which are adapted to functions other than the bearing of spores.

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  • The spores escape generally by means of a distinct aperture which appears in the top of the ball.

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  • "He saw that they increased in size, divided, and became full of filiform spores, then ruptured and poured out their multitudinous progeny into the bodycavity of their insect host.

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  • Finally, he saw the spores accumulate within the cells of the salivary glands, and discovered that they actually passed down the salivary ducts and along the grooved hypopharynx into the seat of puncture, thus causing infection in a fresh vertebrate host" (Sambon).

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  • Gymnosporangium sabinae, one of the rusts (Uredineae) passes one stage of its life-history on living pear leaves, forming large raised spots or patches which are at first yellow but soon become red and are visible on both faces; on the lower face of each patch is a group of cluster-cups or aecidia containing spores which escape when ripe.

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  • This stage in the life-history was formerly regarded as a distinct fungus with the name Roestelia cancellata; it is now known, however, that the spores germinate on young juniper leaves, in which they give rise to this other stage in the plant's history known as Gymnosporangium.

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  • The gelatinous, generally reddish-brown masses of spores - the teleutospores - formed on the juniper in the spring germinate and form minute spores - sporidia - which give rise to the aecidium stage on the pear.

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  • Diseased pear leaves should be picked off and destroyed before the spores are scattered and the various species of juniper on which the alternate stage is developed should not be allowed near the pear trees.

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  • The fungus mycelium grows between the cuticle and the epidermis, the former being ultimately ruptured by numerous short branches bearing spores (conidia) by means of which the disease is spread.

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  • Pear trees may 2, Section of leaf surface showing the also be attacked by a great spores or conidia, c, borne on long variety of insect pests.

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  • A "map" of the spores should be taken by separating a pileus and placing it flat on a piece of thin paper for a few hours when the spores will fall and leave a nature print of the arrangement of the gills which may be fixed by gumming the other side of the paper.

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  • The plankton is divided into (a) the Zoo-plankton (such as the minute crustacea and the eggs and larva of fishes and many other marine animals); and (b) the Phyto-plankton, that is, the minute algae, diatoms, peridinians, some flagellate protozoa, spores of alga, etc. The investigation of the plankton from a new point of view, begun by Hansen in 1889, was continued by Lohmann at Kiel, by Cleve in Sweden, by Gran and Ostenfeldt in Norway and Denmark, and by Herdman, Allen and others in England.

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  • aaK6s, a bag), a botanical term for the membranous sacs containing the reproductive spores in certain lichens and fungi.

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  • In many low organisms, such as the spores of bacteria, the thick, non-conducting wall may preserve the living protoplasm from subjection to external temperatures below freezing point, or above boiling point, but all the evidence goes to show that applications of such cold or heat, if prolonged or arranged so as to penetrate to the living matter, destroy life.

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  • The presence of the volva, and the clear white gills and spores, distinguish this genus from all other agarics.

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  • Portion of the mycelium of the fungus bearing spores (conidia), s, on erect branches, X250.

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  • Ascus from perithecium containing six spores, X30o.

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  • Some of the hyphae which project from the leaf bear spores (conidia), which are constricted off one at a time, and by their means the fungus is distributed (fig.

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  • These are minute, oval, colourless spores, which serve to spread the disease over the vineyard and from place to place.

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  • Single ascus, more enlarged, showing the eight contained spores.

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  • Cercospora Vitis (Cladosporium viticolum), which has club-shaped spores of a green-brown colour, also attacks the leaves; but, unless the season is extremely unfavourable, it does little harm.

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  • The latter is the more serious, as in addition to the actual damage done by the beetle the holes afford entrance to fungus spores, &c. Under the name " horn worms " are included the larvae or caterpillars of species of Protoparce.

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  • The mycelium produced from the spores dropped by the fungus or from the "spawn" in the soil, radiates outwards, and each year's successive crop of fungi rises from the new growth round the circle.

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  • In cannel coals the prevailing constituents are the spores of cryptogamic plants, algae being rare or in many cases absent.

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  • In addition, the great majority have also another method of reproduction, for increasing the number of the parasites in any individual host; this is distinguished as multiplicative or endogenous reproduction, from the propagative or exogenous method (by means of the resistant spores), which serves for the infection of fresh hosts and secures the dissemination and survival of the species.

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  • The spores formed on the delicate grey mould are carried during the summer from one plant to another, thus spreading the disease, and also germinate in the soil where the fungus may remain passive during the winter producing a new crop of spores next spring, or sometimes attacking the scales of the bulbs forming small black hard bodies embedded in the flesh.

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  • This prevents infection from outside and also destroys any spores or fungus mycelium that may have been packed away along with the bulbs.

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  • Only a single pathogenic species can withstand the short boiling to which milk is ordinarily treated in domestic management, and this is the anthrax bacillus containing spores.

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  • The danger from this source is remote, as the microbe does not form spores within the animal body.

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  • Milk so treated will keep at the ordinary room temperature, as the spores of the B.

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  • mesentericus do not develop below 15° C.; but if it be introduced into the alimentary canal of a child the spores will rapidly multiply, and in such cases large quantities of gas, giving rise to flatulency, will be formed, and possibly also poisonous decomposition products of albuminoid matter.

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  • The spores germinate on a damp surface and enter the cortex through small cracks or wounds in the protecting layer.

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  • The disease is peculiarly contagious and infectious, owing to the development of the fungus through the skin, whence spores are freed, which, coming in contact with healthy caterpillars, fasten on them and germinate inwards, giving off corpuscles within the body of the insect.

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  • The algal cells are never known to form spores while part of the lichen-thallus, but they may do so when separated from it and growing free.

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  • Later Bonnier (1886) succeeded in producing fertile thalli by sowing lichen spores and the appropriate algae upon sterile glass plates or portions of bark, and growing them in sterilized air (fig.

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  • There are three methods of reproduction of the lichen: by fragmentation, by soredia, by the formation of fungal spores.

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  • The soredia are the most successful method of reproduction in lichens, for not only are some forms nearly always without spore-formation and in others the spores laregly abortive, but in all cases the spore represents only the fungal component of the thallus, and its success in the development of a new lichen-thallus depends on the chance meeting, at the time of germination, with the appropriate algal component.

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  • The spores themselves may be unicellular without a septum or multicellular with one or more septa.

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  • At other times the spores are divided by both transverse and longitudinal septa producing the muriform (murali-divided) spore so called from the resemblance of the individual chambers to the stones in a wall.

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  • The very large single spores of Pertusaria have been shown to contain numerous nuclei and when they germinate develop a large number of germ tubes.

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  • The spores are ejected from the apothecia and peri thecia as in the fungi by forcible ejacu lation from the asci.

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  • the more important part in lichen distribution as the development of the r1012444 ordinary spores is dependent on their ?,O.° finding the proper alga on the sub- I t.?

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  • - In a number of forms (Endocarpon pusillum, Stigmaatonima cataleptum, various species of Staurothele), however, there is a special arrangement by which the spores are, on ejection, associated with gonidia.

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  • When the spores are thrown out some of these hymenial gonidia, as they are called, are carried with them.

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  • When the spores germinate the germ-tubes surround the algal cells, which now increase in size and become the normal gonidia of the thallus.

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  • b, Asci (thecae) with bilocular spores.

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  • A solution of iodine is also used as a test owing to the blue or wine-red colour which the thallus, hymenium or spores may give with this reagent.

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  • The paraphyses branch and form a network (capillitium) over the asci, the capillitium and ejected spores forming a long persistent powdery mass (mazaedium).

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  • Spores usually two-celled, either with a strongly thickened cross-wall often perforated by a narrow canal or with crosswall only slightly thickened.

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  • In the first case the spores are usually colourless, the second case always brown.

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  • Spores unicellular, parallel-multicellular or muriform, usually colourless, cross-walls usually thin.

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  • - These popular plants are usually increased by means of their spores, the " dust " produced on the back of their fronds.

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  • The spores should be sown in well-drained pots or seed pans on the surface of a mixture of fibrous sifted peat and small broken crocks or sandstone; this soil should be firmly pressed and well-watered, and the spores scattered over it, and at once covered with propagating glasses or pieces of sheet glass, to prevent water or dry air getting to the surface.

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  • The spores may be sown as soon as ripe, and when the young plants can be handled, or rather can be lifted with the end of a pointed flat stick, they should be pricked out into well-drained pots or pans filled with similar soil and should be kept moist and shady.

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  • Spores may be sown as above described, but in a much lower temperature.

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  • The reproductive spores are borne in sacs (asci) which form a dense layer on the surface, appearing like a bloom in July; they are scattered by the wind and propagate the disease.

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  • The reproductive spores are formed in embedded flesh-shaped receptacles (perithecia) and scattered after the leaves have fallen.

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  • fungus, a mushroom), the botanical name covering in the broad sense all the lower cellular Cryptogams devoid of chlorophyll, which arise from spores, and the thallus of which is either unicellular or composed of branched or unbranched tubes or cell-filaments (hyphae) with apical growth, or of more or less complex wefted sheets or tissue-like masses of such (mycelium).

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  • The spores, which may be unior multi-cellular, are either abstricted free from the ends of hyphae (acrogenous), or formed from segments in their course (chlamydospores) or from protoplasm in their interior (endogenous).

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  • It was formerly the custom to include with the Fungi the Schizomycetes or Bacteria, and the Myxomycetes or Mycetozoa; but the peculiar mode of growth and division, the cilia, spores and other peculiarities of the former, and the emission of naked amoeboid masses of protoplasm, which creep and fuse to streaming plasmodia, with special modes of nutrition and spore-formation of the latter, have led to their separation as groups of organisms independent of the true Fungi.

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  • As a rule the nuclei of the mycelium are very minute (1.5-2 µ in Phycomyces), but those of many asci and spores are large and easily rendered visible.

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  • As with other plants, so in fungi the essential process of fertilization consists in the fusion of two nuclei, but owing to the absence of well-marked sexual organs from many fungi, a peculiar interest attaches to certain nuclear fusions in the vegetative cells or in young spores of many forms. Thus in Ustilagineae the chlamydospores, and in Uredineae the teleutospores, each contain two nuclei when young, which fuse as the spores mature.

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  • Morphologically considered, spores are marked by peculiarities of form, size, colour, place of origin, definiteness in number, mode of preparation, and so forth, such that they can be distinguished more or less sharply from the hyphae which produce them.

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  • The only physiological peculiarity exhibited in common by all spores is that they germinate and initiate the production of a new fungus-plant.

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  • Whether a spore results from the sexual union of two similar gametes (zygospore) or from the fertilization of an egg-cell by the protoplasm of a male organ (oospore); or is developed asexually as a motile (zoospore) or a quiescent body cut off from a hypha (conidium) or developed along its course (oidium or chlamydospore), or in its protoplasm (endospore), are matters of importance which have their uses in the classification and terminology of spores, though in many respects they are largely of academic interest.

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  • Klebs has attemped to divide spores into three categories as follows: (I) kinospores, arising by relatively simple cell-divisions and subserving rapid dissemination and propagation, e.g.

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  • In practice these various kinds of spores of fungi receive further special names in the separate groups, and names, more over, which will appear, to those unacquainted with the history, to have been given without any consistency or regard to general principles; nevertheless, for ordi nary purposes these names are far more useful in most cases, owing to their descriptive character, than the proposed new names, which have been only partially accepted.

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  • In some of the simpler fungi the spores are not borne on or in hyphae which can be distinguished from the vege A tative parts or mycelium, but in the vast majority of cases the sporogenous hyphae either ascend free into the air or radiate into the surrounding water as distinct branches, or are grouped into special columns, cushions, layers or complex masses obviously different in colour, consistency, shape and other characters from the parts which gather up and assimilate the food-materials.

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  • c, Conidium emitting zooC. Formation of zoospores by spores.

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  • Other series of modifications arise in which the tissues corresponding to the stroma invest the sporogenous hyphal ends, and thus enclose the spores, asci, basidia, &c., in a cavity.

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  • Another simple case is where the plane or slightly convex surface of the stroma rises at its margins and overgrows the sporogenous hyphal ends, so that the spores, asci, &c., come to lie in the depression of a cavity - e.g.

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  • In such examples as the above we may regard the hymenium (Solenia, Cyphella), zygospores, or asci as truly invested by later growth, but in the vast majority of cases the processes which result in the enclosure of the spores, asci, &c., in a "fructification" are much more involved, inasmuch as the latter is developed in the interior of hyphal tissues, which are by no means obviously homologous with a stroma.

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  • Then a hollow appears in the centre owing to the more rapid extension of the outer parts, and into this hollow the cells lining it put forth short sporogenous branches, from the tips of which the spores (stylospores, c nidia, spermatia) are abstricted.

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  • The outer parts of the mass then differentiate as a wall or investment, and the interior becomes a hollow, into which hyphal ends grow and abstrict the spores.

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  • - Ordinary conidia and similarly abstricted dry spores are so minute, light and numerous that their dispersal is ensured by any current of air or water, and we also know that rats and other burrowing animals often carry them on their fur; similarly with birds, insects, slugs, worms, &c., on claws, feathers, proboscides, &c., or merely adherent to the slimy body.

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  • Passing over the locomotor activity of zoospores (Pythium, Peronospora, Saprolegnia) we often find spores held under tension in sporangia (Pilobolus) or in asci (Peziza) until ripe, and then forcibly shot out by the sudden rupture of the sporangial wall under the pressure of liquid behind - mechanism comparable to that of a pop-gun, if we suppose air replaced by watery sap. Even a single conidium, held tense to the last moment by the elastic cell-wall, may be thus shot forward by a spurt of liquid under pressure in the hypha abstricting it (e.g.

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  • A more complicated case is illustrated by Sphaerobolus, where the entire mass of spores, enclosed in its own peridium, is suddenly shot up into the air like a bomb from a mortar by the elastic retroversion of a peculiar layer which, up to the last moment, surrounded the bomb, and then suddenly splits above, turns inside out, and drives the former as a projectile from a gun.

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  • Such gums are formed abundantly in pycnidia, and, absorbing water, swell and carry out the spores in long tendrils, which emerge for days and dry as they reach the air, the glued spores gradually being set free by rain, wind, &c. In oidial chains (Sclerotinia) a minute double wedge of wall-substance arises in the middle lamella between each pair of contiguous oidia, and by its enlargement splits the separating lamella.

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  • These disjunctors serve as points of application for the elastic push of the swelling spore-ends, and as the connecting outer lamella of cell-wall suddenly gives way, the spores are jerked asunder.

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  • In many cases the slimy masses of spermatia (Uredineae), conidia (Claviceps), basidiospores (Phallus, Coprinus), &c., emit more or less powerful odours, which attract flies or other insects, and it has been shown that bees carry the flagrant oidia of Sclerotinia to the stigma of Vaccinium and infect it, and that flies carry away the foetid spores of Phallus, just as pollen is dispersed by such insects.

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  • Whether the strong odour of trimethylamine evolved by the spores of Tilletia attracts insects is not known.

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  • Thallus septate; spores developed in special type of sporangium, the ascus, the number of spores being usually eight.

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  • The development of the "conidia" as true conidial spores or as zoosporangia may occur in one and the same species (Cystopus candidus, Phytophthora infestans) as in Pythium described above; in other cases the direct conidial germination is characteristic of genera - e.g.

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  • In some cases resting spores are formed inside the host (Chytridium), and give rise to zoosporangia on germination.

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  • They are characterized especially by the zygospores, but the asexual organs (sporangia) exhibit interesting series of changes, beginning with the typical sporangium of Mucor containing numerous endospores, passing to cases where, as in Thamnidium, these are accompanied with more numerous small sporangia (sporangioles) containing few spores, and thence to Chaetocladium and Piptocephalis, where the sporangioles form but one spore and fall and germinate as a whole; that is to say, the monosporous sporangium has become a conidium, and Brefeld regarded these and similar series of changes as explaining the relation of ascus to conidium in higher fungi.

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  • According to his view, the ascus is in effect the sporangium with several spores, the conidium the sporangiole with but one spore, and that not loose but fused with the sporangiole wall.

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  • In addition to sporangia and the conidial spores referred to, some Mucorini show a peculiar mode of vegetative reproduction by means of gemmae or chlamydospores - i.e.

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  • short segments of the hyphae become stored with fatty reserves and act as spores.

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  • These then become surrounded by a cell-wall and form the spores.

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  • These structures cannot 3, then be produced from the product of a single spore nor even from the thalli derived from any two spores.

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  • They are remarkable for their dark spores developed in gall-like excrescences on the leaves, stems, &c., or in the fruits of the host.

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  • The discovery of the yeast-conidia of these fungi, and their thorough investigation by Brefeld, have thrown new lights on the group, as also have the results elucidating the nature of the ordinary dark spores - smuts, bunt, &c. - which by their mode of origin and development are chlamydospores.

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  • Brefeld regarded the promycelium as a kind of basidium, bearing lateral or terminal conidia (comparable to basidiospores), but since the number of basidiospores is not fixed, and the basidium has not yet assumed very definite morphological characters, Brefeld termed the group Hemibasidii, and regarded them as a halfway stage in the evolution of the true Basidiomycetes from Ph co Y Y mycetes, the Tilletia type leading to the true basidium (Autobasidium), the Ustilago type to the proto pm basidium, with lateral spores; but this p m view is based on very poor evidence, so that it is best to place these forms?p, c;,::, as a separate group, the Ustilaginales.

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  • When the flowers form, however, the mycelium sends hyphae into the young ovaries and rapidly replaces the stores of sugar and starch, &c., which would have gone to make the grain, by the soot-like mass of spores so well known as smut, &c. These spores adhere to the grain, and unless destroyed, by "steeping" or other treatment, are sown with it, and again produce sporidia and yeast-conidia which infect the seedlings.

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  • In some cases nuclear division is carried further before spore-formation occurs, and the number of spores is then 16, 32 and 64, &c.; in a few cases the number of spores is less than eight by abortion of some of the eight nuclei.

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  • (After Harper.) Young ascus of Boudiera with eight spores.

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  • (After Claussen.) D, spores.

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  • The sporangium with its endogenous spores has been compared with an ascus, and on these grounds the group is placed among the Ascomycetes - a very doubtful association.

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  • Under other conditions, of which the temperature is an important one, the nucleus in the yeast-cell divides, and each daughter-nucleus again, and four spores are formed in the mother cell, a process obviously comparable to the typical development of ascospores in an ascus.

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  • The fused cell becomes a sporangium, and in it eight spores are developed.

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  • In certain cases single cells develop parthenogenetically, without fusion, each cell producing, however, only four spores.

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  • In the formation of spores the nucleus of the cell divides, the protoplasm collects round the nuclei to form the spores by free-cell formation; the protoplasm (epiplasm) not used in this process becomes disorganized.

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  • If there are two fusions one would expect two reductions, and Harper has suggested that the division of the nuclei into eight in the ascus, instead of into four spores as in most reduction processes, is associated with a double reduction process in the ascus.

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  • Four ripe asci, a i, a2, with eight spores, a 3, a4, with yeast-like conidia abstricted from the spores.

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  • This is typically of a flask-shaped form opening with a small pore at the top. The asci live at the bottom often mixed with paraphyses, while the upper" neck "of the flask is lined with special hyphae, the periphyses, which aid in the ejection of the spores (fig.

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  • The asci are developed in the large dense fruit bodies (cleistothecia) and the spores escape by the decay of the wall.

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  • Owing to the presence of oily globules of an orange-yellow or rusty-red colour in their hyphae and spores they are termed Rust-Fungi.

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  • They are distinguished from the other fungi and the rest of the Basidiales by the great variety of the spores and the great elaboration of the life-history to be found in many cases.

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  • Five different kinds of spores may be present - teleutospores, sporidia (= basidiospores), aecidiospores, spermatia and uredospores (fig.

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  • Whether B, Formation of the first sporethe association of nuclei in the mother-cell (sm), from the ordinary mycelium takes place basal cell (a) of one of the by the migration of a nucleus rows of spores.

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  • In Dacryomyces only two outgrowths and two spores are produced.

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  • In these sporophores (such as the well-known toadstools and mushrooms where the ordinary vegetative mycelium is underground) we have structures specially developed for bearing the basidiospores and protecting them from rain, &c., and for the distribution of the spores - see earlier part of article on distribution of spores (figs.

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  • fruit-bodies which only open after the spores are ripe and then often merely by a small pore.

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  • By the breaking down of the inner tissues the spores often come to lie as a loose powdery mass in the interior of the hollow fruitbody, mixed sometimes with a capillitium.

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  • Spore Distribution: Fulton, "Dispersal of the Spores of Fungi by Insects," Ann.

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  • Spores and Sporophores: Zopf, Die Pilze; also the works of von Tafel and Brefeld.

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  • The primary function of the flower is to bear the spores.

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  • The development of the microsporangia and the contained spores (pollen -grains) P (P g is closely comparable with that of the microsporangia in Gymnosperms or heterosporous ferns.

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  • The mature pollengrain is, like other spores, a single cell; except in the case of some submerged aquatic plants, it has a double wall, a thin delicate wall of unaltered cellulose, the endospore or intine, and a tough outer cuticularized exospore or extine.

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  • The number of chromosomes (see Plants: Cytology) in the nucleus of the two spores, pollen-grain and embryo-sac, is only half the number found in an ordinary vegetative nucleus; and this reduced number persists in the cells derived from them.

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  • The full number is restored in the fusion of the male and female nuclei in the process of fertilization, and remains until the formation of the cells from which the spores are derived in the new generation.

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  • Here the contents of certain cells break up endogenously into a great number of spores, which are distributed as a fine dust.

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  • Resting spores are also known.

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  • The asexual cells are immotile spores arising in fours in sporangia from superficial cells of the thallus.

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  • The spores of Monospora are by some regarded as unicellular propagula.

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  • Thus in Lemaneaceae asexual spores are unknown; in Batracho-spermum, Bonnemaisonia and Polysiphonia byssoides both kinds of sexual cells appear on the same plant; and in some cases the asexual cells may occur in conjunction with either the male or female sexual cells.

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  • The tetraspores may arise by the simultaneous division of the contents of a sporangium, when they are arranged tetrahedrally, or they may arise by two successive divisions, in which case the arrangement may be zonate when the spores are in a row, or cruciate when the second divisions are at right angles to the first, or tetrahedral when the second divisions are at right angles to the first and also to one another.

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  • Polysiphonia sp., transverse section through a branch, and at spores arising from fertilized carpogonium.

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  • Callithamnion sp., tetrasporangium with spores arranged in a and a, b, two auxiliary cells.

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  • There is here obviously a certain parallelism with the case of Bryophyta, where the sporogonium arising from the oospore is epiphytic and partially parasitic upon the female plant, and always culminates in the production of spores.

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  • It is possible, however, that the tetraspore formation should be regarded as comparable with the prolific vegetative reproduction of Bryophyta, and in favour of this view there is the fact that the tetraspores originate on the thallus in a different way from carpospores with which the spores of Bryophyta are in the first place to be compared; moreover, in certain Nemalionales the production of tetraspores does not occur, and the difficulty referred to does not arise in such cases.

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  • ..Bangiaceae - Eti Florideae Eugleneae Chi Iromonadinae Pleurococcaceae - Endosphaeraceae Volvocaceae hlorosphaeraceae � CoNJuGA'rAE, Siphonales Tetrasporaceao Ulvaceae Confdyvaleb Characeae in the culminating stage of Fucus, where the oogonium is separated from the stalk-cell, so that unless it be contended that the Fucus is really a sporophyte which does not produce spores, and that the gametophyte is represented merely by the oogonium and antheridium, there is no semblance of alternation of generation in this case.

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  • The spores of the Aglaozonia form are known to give rise to sexual plants, and the oospore of Cutleria has been observed to grow into rudimentary Aglaozonia.

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  • "Dry rot," which usually attacks the sap-wood, generally starts in a warm damp unventilated place, and is caused by the growth of fungi, some of which are visible to the naked eye, some microscopic. The spores from the fungi on the decayed wood float in the air and alight on any adjacent timber, infecting this also if the conditions be favourable.

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  • The spores of the fungus will find a way through brickwork, concrete and similar material, in order to reach woodwork that may be on the other side.

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  • (3) The Institute is in entire agreement with the commission as to the value of 5% carbolic acid in restraining tetanus growth when added to plague prophylactic, and its experiments emphasize still further the importance of this addition in preventing growth and toxin formation in a vaccine which might be liable to the possibility of contamination with spores of tetanus.

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  • On the destruction of the leaves the fungus either descends the stem by the interior or the spores are washed by the rain to the tubers in the ground.

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  • In either case the tubers are reached by the fungus or its spores, and so become diseased.

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  • The germinating spores are not only able to pierce the leaves and stems of the potato plant, and so gain an entry to its interior through the epidermis, but they are also able to pierce the skin of the tuber, especially in young examples.

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  • It is therefore obvious that, if the tubers are exposed to the air where they are liable to become slightly cracked by the sun, wind, hail and rain, and injured by small animals and insects, the spores from the leaves will drop on to the tubers, quickly germinate upon the slightly injured places, and cause the potatoes to become diseased.

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  • The last measure prevents the germination of the spores of the fungus on the leaves, and is a most useful mode of checking the spread of the disease; to be successful in its use, however, entails care in the preparation of the spray and thoroughness in its application.

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  • It is characterized by the curling of the leaves, which later show black A spots due to the production of numerous dark spores in patches on the diseased leaves.

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  • 3, Section through diseased tissue showing dark masses of spores.

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  • 4 and 5, Tissue-cell, more highly magnified, showing enclosed spores.

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  • The spores of the fungus pass the winter in the soil and the delicate mycelium attacks the young shoots in the summer.

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  • The first signs of this fungus is the appearance of small white tufts of mycelium bursting through the skin of the tuber, the spores of the fungus being carried at the tips of the threads forming these tufts.

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  • The pieces of dried-up potato with the spores of Nectria upon them are a source of infection in the succeeding year, and care should be taken that diseased tubers are not planted.

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  • The fact that Schizomycetes produce spores appears to have been discovered by Cohn in 1857, though it was expressed dubiously in 1872; these spores had no doubt been observed previously.

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  • In 1876, however, Cohn had seen the spores germinate, and Koch, Brefeld, Pratzmowski, van Tieghem, de Bary and others confirmed the discovery in various species.

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  • No case' of so-called " spontaneous generation " has withstood rigid investigation; but the discussion contributed to more exact ideas as to the ubiquity, minuteness, and high powers of resistance to physical agents of the spores of Schizomycetes, and led to more exact ideas of antiseptic treatments.

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  • Koch in 1876 published his observations on Davaine's bacilli, placed beyond doubt their causal relation to splenic fever, discovered the spores and the saprophytic phase in the life-history of the organism, and cleared up important points in the whole question (figs.

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  • - The various phases of germination of spores of Bacillus ramosus (Fraenkel), as actually observed in hanging drops under very high powers.

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  • Germinating spores in various stages, more highly magnified, and showing the different ways of escape of the filament from the spore-membrane.

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  • Various stages in the development of the endogenous spores in a Clostridium - the small letters indicate the order.

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  • Endogenous spores of the hay bacillus.

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  • C. A chair of cocci of Leuconostoc mesenterioides, with two " resting spores," i.e.

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  • Clostridium - one cell contains two spores.

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  • Spirillum containing many spores (a), which are liberated at b by the breaking up of the parent cells.

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  • c, d, e, f, successive stages in the development of the spores.

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