Text-book of botany, morphological and physiological . ow in these caseswithin the mother-cell a creeping motion whichlasts for a considerabletime before they becomeconnected into a surface(Pediastrum), or in the formof a sac-hke hollow net(Hydrodictyon), and formby their growth a the same manner thesister-cells (endosperm) which arise in the embryo-sac of Phanerogams by free-cell-formation, unite with one another and with the wall of the embryo-sac itself, con-tinuing then to develop as a continuous tissue and to increase by division. In Fungi and Lichens the formation of tissue ori
Text-book of botany, morphological and physiological . ow in these caseswithin the mother-cell a creeping motion whichlasts for a considerabletime before they becomeconnected into a surface(Pediastrum), or in the formof a sac-hke hollow net(Hydrodictyon), and formby their growth a the same manner thesister-cells (endosperm) which arise in the embryo-sac of Phanerogams by free-cell-formation, unite with one another and with the wall of the embryo-sac itself, con-tinuing then to develop as a continuous tissue and to increase by division. In Fungi and Lichens the formation of tissue originates by the apical growthof juxtaposed thin filaments consisting of rows of cells (the hyphse), and differentorders of branchlets of them; each filament grows by itself, increasing the number ofits cells by division, and branches copiously; but this takes place in such a mannerthat the different hyphse undergo a similar development at definite spots on the wholebody of the Fungus or Lichen; thus arise surfaces, strings, hollow structures, &c.,. Fig. i^—Pediastrum granulaUiin (after A. Braun) (X400). A a disc consisting ofcells grown together; at g the innermost layer of a cell-wall is protruding; it containsthe daughter-cell* resulting from division of the green protoplasm ; at t are variousstates of division of the cells ; sp the fissures in the already empty cell-walls ; B the innerlamella of the mother-cell-wall which has entirely escaped (greatly enlarged); b containsthe daughter-cells (g), these are in active creeping motion ; C the same family of cells4j hours after its birth, 4 hours after the small cells have come to rest; these havearranged themselves into a disc, which is already beginning to develop into onesimilar to A. DEFINITION. 69 ^vhich show a common growth, and yet consist of single elementary structuresdeveloping individually (Fig. 55). With the exception, however, of the instances named, and of some alliedones, the formation in the vegetable kingdom of
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectbotany, bookyear1875
