. Morphology of gymnosperms. Gymnosperms; Plant morphology. ^'.^^^y '^'- 0¥' Fig. 110.—Dioon edide: microspo- rangium; detail showing thickened epider- mis, wall cells, tapetum, and sporogenous tissue; X250.—After Chamberlain (63). does not regard the small spaces less than the variation in the out- put of individual sporangia of average size. It is recognized that this formula could be used only when spores are very small and sporangia very large. Esti- mating in this way. Chamber- lain (63) found the output of spores in Dioon edule to be 30,000; Miss F. Grace Smith found it to be 26,000 in E
. Morphology of gymnosperms. Gymnosperms; Plant morphology. ^'.^^^y '^'- 0¥' Fig. 110.—Dioon edide: microspo- rangium; detail showing thickened epider- mis, wall cells, tapetum, and sporogenous tissue; X250.—After Chamberlain (63). does not regard the small spaces less than the variation in the out- put of individual sporangia of average size. It is recognized that this formula could be used only when spores are very small and sporangia very large. Esti- mating in this way. Chamber- lain (63) found the output of spores in Dioon edule to be 30,000; Miss F. Grace Smith found it to be 26,000 in En- cephalartos villosus, 8,000 in Ceratozamia, and 500-600 in Zamia floridana. In general the results favor the view that the output is larger in the more primitive forms and decreases toward the more highly special- ized Fig. III.—Dioon edide: microsporangium; two of the sporangia of a sorus, showing extensive sporogenous tissue and scanty tapetum; two-celled hairs growing on the base of the sporangium; X5S.—^After Chambeklain (63). Since the spore is regarded as the first cell of the gametophyte generation, it will be considered in the section on the male 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. Part I. Gymnosperms. Chicago, University of Chicago Press
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