. Morphology of gymnosperms. Gymnosperms; Plant morphology. CORDAITALES 179 nitely referred as yet to either Cordaitales or Cycadofilicales, similar groups of internal cells have been found, as in Stephanaspermum (p. 50), indicating that the male gametophyte among paleozoic seed plants must have been more primitive in structure, in the amount of either prothallial or spermatogenous tissue or both, than in living seed plants. It is interesting to note, in this connection, that an excess of male prothallial tissue, as compared with the other living gymnosperms, has been found among the podocarps
. Morphology of gymnosperms. Gymnosperms; Plant morphology. CORDAITALES 179 nitely referred as yet to either Cordaitales or Cycadofilicales, similar groups of internal cells have been found, as in Stephanaspermum (p. 50), indicating that the male gametophyte among paleozoic seed plants must have been more primitive in structure, in the amount of either prothallial or spermatogenous tissue or both, than in living seed plants. It is interesting to note, in this connection, that an excess of male prothallial tissue, as compared with the other living gymnosperms, has been found among the podocarps and ap Fig. 210.—Cycadinocarpus angustodunensis: longitudinal section of upper part of ovule; mi, micropyle; int, integument; pc, pollen chamber with pollen grains; nu, nuceUus; ar, archegonia; fr, female gametophyte.—After Renault (2). In some of the sections of the seeds of Cordaitales, the mature embryo sac, containing the female gametophyte (endosperm) with its - archegonia, has been found, as in a species of Cycadinocarpus (fig. 210). In the figure cited it is evident that the endosperm has encroached upon the nucellus almost to the testa, and that it has devel- oped a characteristic endosperm beak which supports the settling nucellar beak, as in Ginkgo, in which form Hirase aptly likens the endosperm beak to a "tent ; Two archegonia are evident in the section, and opened into the archegonial chamber which sur- rounded the base of the "tent pole" like a moat. This peculiar endosperm beak is one of the several characters that show a close connection between Cordaitales and 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; Coulter, John Merle, 1851-1928. Morphology of spermatophytes
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