Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . It should be noted, however,that the cells of the threadlike forms exhibit the habitsof the one-cell forms, and it is questionable whether suchforms should be regarded as multicellular plants: thethread might rather be looked upon as a series of one-cell plants, which are independent units in all pointsbut that of their attachment in rows. The Desmid cell, which exhibits great variety of formin different species, almost invariably displays two quitesymmetrical halves, which are very frequ
Plant-life, with 74 full-page illus., 24 being from photos, by the author and 50 in colour from drawings . It should be noted, however,that the cells of the threadlike forms exhibit the habitsof the one-cell forms, and it is questionable whether suchforms should be regarded as multicellular plants: thethread might rather be looked upon as a series of one-cell plants, which are independent units in all pointsbut that of their attachment in rows. The Desmid cell, which exhibits great variety of formin different species, almost invariably displays two quitesymmetrical halves, which are very frequently markedoff from each other by a constriction forming a sort ofneck, or waist, between them. The cell-wall, which isoften sculptured, lobed, covered with protuberances, andfurnished with pores, is in two halves or valves, the edgesof which meet at the constriction, or median cell-nucleus occurs in the median plane, and acolour-bearing body (chromatophore), which may beradiate in form, or composed of several plates, occupiesthe greater part of each half of the cell. Pyrenoids, Plate 7. VauchMa, Sexual reproduction ; 2 „ Zygospores formed in one filament ? o. Oogonium . ^ s. Spermatozoids 3 „ Gcrmmation of zygospore ^ 4. Vaucheria ...nlh, branched filament 8, 9, 10, 11, Vd^ox ghhator. See text. with root processes 12 to 19. Desmid. Cmmarium botrytis 5. „ Asexual reproduction ; zoospore Propagation by division (Figs. 13 to 15) escaping Sexual Veproduction (Figs. 16 to 19i 6- „ Zoospore free 20. Desmid. Cloiurium lunula 21. Diatom, ^innularia >irldis THE DESMIDS 33 wMch are tiny proteid bodies, are found in the chromato-phores, and during assimilation, starch, granules areformed round them. The chromatophores are enclosedin transparent protoplasm, which appears under themicroscope between the coloured area and the pores in the cell-wall, already spoken of, are exitsfor fine threads of protoplasm, which gather on theoutside of
Size: 1309px × 1908px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1915
