. Morphology of angiosperms (Morphology of spermatophytes. Part II). Angiosperms; Plant morphology. CHAPTER VIII THE ENDOSPERM The endosperm of Gymnosperms seems to be clearly the vegetative tissue of the female gametophyte, but the morpho- logical nature of the endosperm of Angiosperms (Fig. 74) is not so clear. The ger- mination of the megaspore begins, as in Gymnosperms, with free and simul- taneous nuclear di- vision. In Gymno- sperms this con- tinues for some time and is re- placed by cell-for- mation, giving rise to an extensive tis- sue bearing arche- gonia, while in An- giosperms usual
. Morphology of angiosperms (Morphology of spermatophytes. Part II). Angiosperms; Plant morphology. CHAPTER VIII THE ENDOSPERM The endosperm of Gymnosperms seems to be clearly the vegetative tissue of the female gametophyte, but the morpho- logical nature of the endosperm of Angiosperms (Fig. 74) is not so clear. The ger- mination of the megaspore begins, as in Gymnosperms, with free and simul- taneous nuclear di- vision. In Gymno- sperms this con- tinues for some time and is re- placed by cell-for- mation, giving rise to an extensive tis- sue bearing arche- gonia, while in An- giosperms usually only eight free nu- clei are formed be- Fig. 74.âTwo modes of initiating the formation of endo- f Ore an e0'0, is Orffan- sperm. A, Naias major, illustrating free nuclear divi- ⢠,°. sion ; there are four free nuclei belonging to the endo- lzeu and iertlliza- sperm, the lower free nucleus being that of the upper tion takes place. In antipodal; x 175. B, Datura laevis, nuclear division both cases endo- followed immediately by formation of wall; x 225.â â â t After Guignard.*2. 4e sperm is formed after fertilization; but in Gymnosperms it is a continuation of cell division, while in Angiosperms it usually begins with nuclear fusion followed by simultaneous and often free nuclear 165. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Coulter, John Merle, 1851-1928; Chamberlain, Charles Joseph, b. 1863. New York, D. Appleton
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