The root-hairs penetrate between masses of the hyphae of the Fungus.
Cells of this type are often called trumpet-hyphae (though they have no connection with the hyphae of Fungi), and in some genera of Laminariaceae those at the periphery of the medulla simulate the sieve-tubes of the higher plants in a striking degree, even (like these latter) developing the peculiar substance callose on or in the perforated cross-walls or sieve-plates.
A solid fungal body may usually be seen to consist of separate hyphae, but in some cases these are so bent and closely interwoven that an appearance like that of ordinary parenchymatous tissue is obtained in section, the structure being called pseudo parenchyrna.
In many forms its hyphae are particularly thick-walled, and may strikingly resemble the epidermis of a vascular plant.
The formation of a massive body naturally involves the localization of the absorptive region, and the function of absorption (which in the simpler forms is carried out by the whole of the vegetative part of the mycelium penetrating a solid or immersed in a liquid substratum) is subserved by the outgrowth of the hyphae of the surface-layer of that region into rhizoids, which, like those of the Algae living on soil, resemble the root-hairs of the higher plants.
The internal tissue of the body of the solid higher Fungi, particularly the elongated stalks (stipes) of the fructifications of the Agarics, consists of hyphae running in a longitudinal direction, which no doubt serve for the conduction of organic food substances, just as do the trumpet-hyphae, similar in appearance, though not in origin, of the higher Brown Seaweeds.
The internal tissues, either consisting of obvious hyphae or of pseudoparenchyma, may also serve as a storehouse of plastic food substances.
Some make their way through the cells of the outer part of the cortex towards the root-tip, and form a mycelium or feltwork of hyphae, which generally occupies two or three layers of cells.
The food so absorbed passes to the outer cortical mycellum, and from this tc the inner hyphae, which appear to be the organs of the interchangi of substance, for they are attracted to the neighborhood of thi nuclei of the cells, which they enter, and iii which they form agglom erations of interwoven filaments.
The inability to enter the cells may be due to the lack of chemotactic bodies, to incapacity to form cellulose-dissolving enzymes, to the existence in the hostcells of antagonistic bodies which neutralize or destroy the acids, enzymes or poisons formed by the hyphae, or even to the formation and excretion of bodies which poison the Fungus.
The mildew is in its turn attacked by a fungus of the same tribe, Cicinnobolus Cesatii, which lives parasitically within the hyphae of its host, and at times even succeeds in destroying it.
The mycelium of Sphaceloma grows just beneath the cuticle of the vine, through which it soon bursts, giving rise to a number of minute hyphae, which bear conidia.
The hyphae of the mycelium of this fungus are septate, with numerous short branches.
The green (or blue-green) cells were termed gonidia by Wallroth, who looked upon them as asexual reproductive cells, but when it was later realized that they were not reproductive elements they were considered as mere outgrowths of the hyphae of the thallus which had developed chlorophyll.
The majority of the lichens, however, possess a stratified thallus in which the gonidia are found as a definite layer or layers embedded in a pseudoparenchymatous mass of fungal hyphae, i.e.
By the fusion of the hyphae in the middle of the mycelium a pseudo-parenchymatous cortical layer has begun to form.
Collema) or may be fixed more or less closely to it by special hyphae or rhizoids.
500 times.) A branched filiform thallus of Stigonema with the hyphae of the fungus growing through its gelatinous membranes.
Extremity of a branch of the thallus with a young lateral branch a; h, hyphae; g, cells of the alga; gs, the apex of the thallus.
The exact relation of gonidia and hyphae has been investigated e specially by Bornet and also by Hedlund, and very considerable differences have been shown to exist in different genera.
In many other cases, especially those algae possessing Pleurococcus as their gonidia, there are no penetrating hyphae, but merely From Strasburger's Lehrbuck der Botanik, by permission of Gustav Fischer.
These were investigated by Tulasne in 1853, who gave them the name spermogonia The lower, ventral portion of the sperm09' gonium is lined by delicate hyphae, the sterigmata, which give origin to minute colourless cells, the spermatia.
M, Medullary hyphae of u, Under rind.
950, B 650 times.) The alg"; s in all cases indicated by the letter g, the assailing hyphae by h.
Cases the reduction goes still farther and the ascogenous hyphae instead of developing from the ascogonia are derived directly from the vegetative hyphae.
In other lichens we should expect to find the ascogenous hyphae arising directly from the vegetative hyphae as in Humaria rutilans among the ordinary fungi, where the process is associated with the fusion of vegetative nuclei.
Clavaria mucida, however, h a s apparently some claims to be considered as a Basidiolichen, since the base of the fruit body and the thallus from which it arises, according to Coker, always shows a mixture of hyphae and algae.
The algal cells are usually controlled in their growth by the hyphae and are prevented from forming zoospores, and in some cases, as already described, the algal cells are killed sooner or later by the fungus.
The wall of the hyphae of the fungus give in the young state the ordinary reactions of cellulose but older material shows somewhat different reactions, similar to those of the so-called fungus-cellulose.
- Many lichens, as is well known, exhibit a vivid colouring which is usually due to the incrustation of the hyphae with crystalline excretory products.
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).
Compound sporophores arise when any of the branched or unbranched types of spore-bearing hyphae described above ascend into the air in consort, and are more or less crowded into definite layers, cushions, columns or other complex masses.
The same laws apply to the individual hyphae and their branches as to simple sporophores, and as long as the conidia, sporangia, gametes, &c., are borne on their external surfaces, it is quite consistent to speak of these as compound sporophores, &c., in the sense described, however complex they may become.
Among the simplest cases are the sheet-like aggregates of sporogenous hyphae in Puccinia, Uromyces, &c., or of basidia in Exobasidium, Corticium, &c., or of asci in Exoascus, Ascocorticium, &c. In the former, where the layer is small, it is often termed a sorus, but where, as in the latter, the sporogenous layer is extensive, and spread out more or less sheet-like on the supporting tissues, it is more frequently termed a hymenium.
Another simple case is that of the columnar aggregates of sporogenous hyphae in forms like Stilbum, Coremium, &c. These lead FIG.
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).
They extend back beyond the Carboniferous, where they occur as hyphae, &c., preserved in the fossil woods, but the best specimens are probably those in amber and in siliceous petrifactions of more recent origin.
Individual hyphae or their branches often exhibit specializations of form.
Many parasitic hyphae put out minute lateral branches, which pierce the cell-wall of the host and form a peg-like (Trichosphaeria), sessile (Cystopus), or stalked (Hemileia), knot-like, or_a B FIG.
In Rhizopus certain hyphae creep horizontally on the surface of the substratum, and then anchor their tips to it by means of a tuft of short branches (appressorium), the walls of which soften and gum themselves to it, then another branch shoots out from the tuft and repeats the process, like a strawberry-runner.
Many fungi (Phallus, Agaricus, Fumago, &c.) when strongly growing put out ribbon-like or cylindrical cords, or sheet-like mycelial plates of numerous parallel hyphae, all growing together equally, and fusing by anastomoses, and in this way extend long distances in the soil, or over the surfaces of leaves, branches, &c. These mycelial strands may be white and tender, or the outer hyphae may be hard and black, and very often the resemblance of the subterranean forms to a root is so marked that they are termed rhizomorphs.
The outermost hyphae may even put forth thinner hyphae, radiating into the soil like root-hairs, and the convergent tips may be closely appressed and so divided by septa as to resemble the root-apex of a higher plant (Armillaria mellea).