. Principles of the anatomy and physiology of the vegetable cell. Plant cells and tissues. THE VEGETABLE CELL. lis Fig, 49. out into a more or less flat disk (tlie thecal layer); in the covered- fruited, it remains enclosed in the thallus. In each of the parent- cells eight spores are formed by free cell formation, and in very many cases these form two, four or a greater number of secondary cells in their interior. Very few observations' have been made on the germination of these spores According to HoUe (" ZurEnt- wlckeliingsg, von Borrera ciliaris/'—On the development of 5. ciliaris, Di
. Principles of the anatomy and physiology of the vegetable cell. Plant cells and tissues. THE VEGETABLE CELL. lis Fig, 49. out into a more or less flat disk (tlie thecal layer); in the covered- fruited, it remains enclosed in the thallus. In each of the parent- cells eight spores are formed by free cell formation, and in very many cases these form two, four or a greater number of secondary cells in their interior. Very few observations' have been made on the germination of these spores According to HoUe (" ZurEnt- wlckeliingsg, von Borrera ciliaris/'—On the development of 5. ciliaris, Diss. 1848, Gottingen), the secondary cells break through the primary spore cell as filaments, and are con- verted into cells outside the spore. According to Meyer's account (" Nebenstunden mein. Beschaftig- ung/' 175), the outer membrane of the spore is not torn, and when a number of spores germinate side by side, the filaments into which they grow out be- come blended together, and contribute jointly to the formation of a new plant. According to the observations of Tulasne (" Vln- stitut," No 849), the inner spore-coat, both of simple and compound spores, grows out into one or more filaments, which soon ramify and acquire septa, and whose short interlacing branches form little cushions, upon which little colourless cells accumu- late, and in which the green cells forming the rudi- ments of the cortical layer of the new plant, make their appearance. We meet with a far greater complication of phe- nomena when we look towards the spores of the Algse, even though here no co-operation of two sexes occurs. This latter may indeed seem doubtful in a number of Algas, in wliich a so-called coagulation occurs, but a more minute examination of this process shews that it bears no analogy to sexual reproduction. This conjugation presents itself most distinctly in the so-called GonjugatOB (the genera—Zygnema^ fig. 49, two ceiis of zy^^ —Tyndaridea, Mougeotia, Staurocarpus
Size: 1601px × 1561px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1850, booksubjectplantcellsandtissues
