. Elementary botany. Botany. FURTHER STUDTES OA' G VMJVOSPERAfS. In comparing the female prothallium of the gj'ranosperms with that of (he fern group we .st;e a remarkable change has taken place. The female pro- thallium of the gymno- Es -J^ p sperms is very much j\ « 1 I ^_.^^^ reduced in size. Espe- cially, it no longer leads an independent existence from the sporophyte, as is the case with nearly all the fern group. It remains enclosed within the maerosporangium (in cvcas if not fertilized it somii-limi^s grows outside o[ tlie maerosporangium and becomes green), and derives its nourishment
. Elementary botany. Botany. FURTHER STUDTES OA' G VMJVOSPERAfS. In comparing the female prothallium of the gj'ranosperms with that of (he fern group we .st;e a remarkable change has taken place. The female pro- thallium of the gymno- Es -J^ p sperms is very much j\ « 1 I ^_.^^^ reduced in size. Espe- cially, it no longer leads an independent existence from the sporophyte, as is the case with nearly all the fern group. It remains enclosed within the maerosporangium (in cvcas if not fertilized it somii-limi^s grows outside o[ tlie maerosporangium and becomes green), and derives its nourishment through it from the sporo- phyte, to which the latter remains organically con- nected. This condition of the female prothallium of the gymnosperms fig' 374- necessitated a special Gingko biloba. --J, mature pollen grain ; /^.germinating adaptation of the male pollen grain, the branched tube entering among the cells *i ir â i *i â . of the micellus; /:>, exhie (outer wall of fpore); J\, pro- prothallllira in order that thallial cell; /-'.,â aiitheridial cell (divides later to form stalk the sperm cells ma\" reach ell and generative cell); /'g. \'egetat'\-e cell ; /'^i. \'acuoles ;. JVc, nucellus. (After drawings by Hirase and Ikenf).) and fertilize the egg 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 Atkinson, George Francis, 1854-1918. New York : H. Holt
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