. Morphology of gymnosperms. Gymnosperms; Plant morphology. Figs. 105-109.—Stangeria paradoxa: development of microsporangium; fig. 105, section showing two of the four cells forming the archesporial plate; fig. 106, each cell of the plate divided into an inner primary sporogenous cell (shaded) and an outer primary wall cell; fig. 107, a more advanced stage; fig. 108, still more advanced stage, showing tapetum (shaded) and sporogenous cells (j); fig. 109, mature microsporan- gium; <, tapetum; w, crushed cells of the wall; figs. 105-108, X266; fig. 109, X66.— After Lang (22). The output of s
. Morphology of gymnosperms. Gymnosperms; Plant morphology. Figs. 105-109.—Stangeria paradoxa: development of microsporangium; fig. 105, section showing two of the four cells forming the archesporial plate; fig. 106, each cell of the plate divided into an inner primary sporogenous cell (shaded) and an outer primary wall cell; fig. 107, a more advanced stage; fig. 108, still more advanced stage, showing tapetum (shaded) and sporogenous cells (j); fig. 109, mature microsporan- gium; <, tapetum; w, crushed cells of the wall; figs. 105-108, X266; fig. 109, X66.— After Lang (22). The output of spores has been estimated by Miss F. Grace Smith (56) and by Chamberlain (63). When spores are very small and closely packed together, and the spore mass is nearly spherical, the number in a sporgjigium may be estimated by the formula ^ttR^. To apply the formula it is necessary only to count the number of spores in a radius from the center of the sporangium to the tapetum, sub- stitute this number for R in the formula, and make the calculation. There is some error because the spore mass may not be exactly. 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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