The tissues of the bud become differentiated into ectoderm and endoderm, and the endoderm of the bud becomes secondarily continuous with that of the parent, but no part of the parental endoderm contributes to the building up of the daughter-polyp. Lang regarded this method of budding as universal in polyps, a notion disproved by O.
All the tissues external to the cork are cast off by the plant.
According to Hinds they feed chiefly on the green tissues, which " are punctured by the piercing mouth-parts and the sap withdrawn by suction.
The adult stage of this form is the Filaria loa found in the subcutaneous tissues of the limbs.
6 1 Iwanzov believes it to be contained within the thread itself before discharge, and to be introduced into the tissues of the prey by the eversion of the thread.
In many Leptomedusae the otocysts are very small, inconspicuous and embedded completely in the tissues; hence they may be easily overlooked in badly-preserved material, and perhaps are present in many cases where they :: r simplest condition of the otocyst is a freely projecting club, a so-called (figs.
The living tissues at the surface are cut off from the underlying dead portions by horizontal partitions termed tabulae, which are formed successively as the coenosteum increases in age and size.
Fragments of wood not infrequently occur, with the tissues well-preserved by impregnation with the resin; while leaves, flowers and fruits are occasionally found in marvellous perfection.
It is convenient here to define the two chief types of cell-form which characterize tissues of the higher plants.
The term parenchyma is applied to tissues whose cells are isodiametric or cylin.drical in shape, prosenchyma tissues consisting of long narrow cells, with pointed ends.
In whatever way the tissues are originally formed, however, the main features of their differentiation are the same.
The internal tissues, either consisting of obvious hyphae or of pseudoparenchyma, may also serve as a storehouse of plastic food substances.
Morphological identity) between the differentiated tissues of an Anthocerotean sporogonium and those of the sporophyte in the higher plants.
Thus the histological differentiation of the sporogonium of the higher mosses is one of considerable complexity; but there is here even less reason to suppose that these tissues have any homology (phylogenetic community of origin) with the similar ones met with in the higher plants.
The root differs from the shoot in the characters of its surface tissues, in the absence of the green assimilative pigment chlorophyll, in the arrangement of its vascular system and in the mode of growth at the apex, all features which are in direct relation to its normally subterranean life and its fixative and absorptive functions.
Special tissues (stereom) may be developed for this purpose in the cortex, or in immediate connection.
Isolated celh (idioblasts), thickened in various ways, are not uncommonly founc supporting the tissues of the leaf.
Associated with it are other tissues, consisting of parenchyma, mainly starchy, and in the Phanerogams particularly, of special stereom.
These collateral bundles are separated from one another by bands of conjunctive tissues called primary medullary rays, which may be quite narrow or of considerable width.
The triple division of tissues is laid down in most cases at 1 very early period of developmentin the flowering plants usuall3 before the resting stage is reached.
On germination of the seed the radicle first grows out, increasing in size as a whole, and soon adding to its tissues by cell division at its apical growing-point.
Differentiation of the xylem progresses outwards, of the phloem inwards, but the two tissues never meet in the centre.
Tissues after differentiation from the primary men- Tissues.
Stems. But in nearly all perennial Dicotyledons, in all dicotyledonous and gymnospermous trees and shrubs and in fossil Pteridophytes belonging to all the great groups, certain layers of cells remain meristematic among the permanent tissues, or after passing through a resting stage reacquire menstematic properties, and give rise to secondary tissues.
The formation of secondary tissues is characteristic of most woody plants, to whatever class they belong.
It is essentially a living tissue, and serves to place all the living cells of the secondary vascular tissues in communication.
The tissue-elements just described are found only in the more complicated secondary vascular tissues of certain Dicotyledons.
A considerable evolution in complexity can be traced in passing from the simplest forms of xylem and phloem found in the primary vascular tissues both among Pteridophytes and Phanerogams to these highly differentiated types.
In the secondary tissues of Dicotyledons we may have, as already described, considerably more differentiation of the cells, all the varieties being referable, however, on the one hand to the tracheal or sieve-tube type, on the other to the parenchyma type.
In some cases special secreting tissues, resin ducts, oil glands, laticiferous tissue, crystal sacs, &c., may be developed among the ordinary secondary vascular elements.
Provision is made for gaseous interchange between the internal tissues and the external air after the formation of cork, by the development of lenticels.
The complex system of dead and dying tissues cut off by these successive periderms, together with the latter themselves in fact, everything outside the innermost phellogen, constitutes what is often known botanically as the bark of the tree.
History and Bibliography.The study of plant anatomy was begun in the middle of the seventeenth century as a direct result of the construction of microscopes, with which a clear view of the structure of plant tissues could be obtained.
The new work largely centred round a discussion of the nature and origin of vessels, conspicuous features in young plant tissues which thus acquired an importance in the contemporary literature out of proportion to their real significance in the construction of the vascular plant.
He took her arms and sat her in a chair, handed her a fistful of tissues, and knelt.
I've figured out which tissues are the softest.
Many species of Thysanoptera are known to be habitually parthenogenetic. The eggs are laid on the food-plant, those females possessed of an ovipositor cutting through the epidermis and placing their eggs singly within the plant-tissues; a single female may take five or six weeks to deposit all her eggs.
The classification into epithelial organs, connective tissues, and the more specialized muscle and nerve, was largely due to him; and he proved the presence of neuroglia in the brain and spinal cord, discovered crystalline haematoidine, and made out the structure of the umbilical cord.
Amphibrachium grows in the tissues of a sponge, Euplectella, and protrudes its hydranth into the canal-system of the sponge; and Lar grows on the tubes of the worm Sabella.
This takes the form of long usually richly branched tubes which penetrate the other tissues of the plant mainly in a longitudinal direction.
Thus the structure of an old thickened root approximates to that of an old thickened stem, and so far as the vascular tissue is concerned can often only be distinguished from the latter by the position and orientation of the primary xylems. The cambium of the primary root, together with the tissues which it forms, is always directly continuous with that of the primary stem, just in the same way as the tissues of the primary stele.
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.
He took her arms and sat her in a chair, handed her a fistful of tissues, and knelt.
The town is noted for its fruit, especially its vines; and it exports tissues, carpets, hides, yellow berries and dried fruit.
The adult worm, which is of extremely minute size, the male being only Fi l sth and the female s of an inch in length inhabits the alimentary canal of man and many other carnivorous mammalia; the young bore their way into the tissues and become encysted in the muscles - within the muscle-bundles according to Leuckart, but in the connective tissue between them according to Chatin and others.
The principal exports are silk and cotton tissues, live stock, wines, spirits and oils; corn, flour, macaroni and similar products; and minerals, chiefly sulphur.
The so-called "pure" acid is applied to infected living tissues, especially to tuberculous sinuses or wounds, after scraping them, in order to destroy any part of the tuberculous material still remaining.
Its power depends on the fact that it is slowly decomposed by the tissues, and free iodine given off.
In this way we may distinguish, first, vegetative reproduction, the result of discontinuous growth of the tissues and cell-layers of the body as a whole, leading to (I) fission, (2) autotomy, or (3) vegetative budding; secondly, germinal reproduction, the result of the reproductive activity of the archaeocytes or germinal tissue.
The coenosteum increases in size by new growth at the surface; and in the deeper, older portions of massive forms the tissues die off after a certain time, only the superficial region retaining its vitality down to a certain depth.
In nearly all plants which produce secondary vascular tissues by means of a cambium there is another layer of secondary meristem arising externally to, but in quite the same fashion as, Ph II
Alondra walked into the room with some tissues and a damp rag.
"I thought you might need these," she said, handing the rag to Carmen and setting the box of tissues on a small table beside her.
Tucking some tissues into her purse, she joined Bill and Katie in the living room.