Elementary botany . to the members of the fern group, especially the ferns is at once suggested by the form ofthe leaves. The stem is short and leaves have a stout midrib andnumerous narrow pinnae. In the centerof this rosette of leaves are numeroussmaller leaves, closely overlapping likebud scales. If we remove one of theseat the time the fruit is forming we see thatin general it conforms to the plan of thelarge leaves. There are a midrib and anumber of narrow pinnae near the freeend, the entire leaf being covered withwoolly hairs. But at the lower end, inplace of th
Elementary botany . to the members of the fern group, especially the ferns is at once suggested by the form ofthe leaves. The stem is short and leaves have a stout midrib andnumerous narrow pinnae. In the centerof this rosette of leaves are numeroussmaller leaves, closely overlapping likebud scales. If we remove one of theseat the time the fruit is forming we see thatin general it conforms to the plan of thelarge leaves. There are a midrib and anumber of narrow pinnae near the freeend, the entire leaf being covered withwoolly hairs. But at the lower end, inplace of the pinnae, we see oval are the macrosporangia (ovules) of cycas, and correspond to the macrosporangia of selaginella, and the leaf is the macrosporophyll. 628. Female prothallium of cycas.—In figs. 367, 368, areshown mature ovules, or macrosporangia, of cycas. In 368, whichis a roentgen-ray photograph of 367, the oval prothallium can beseen. So in cycas, as in selaginella, the female prothallium is 311. Fig. 366Macrosporophyllrevoluta. of Cycas 312 MORPHOLOG Y. developed entirely inside of the macrosporangium, and derivesthe nutriment for its growth from the cycas plant, which is the
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Keywords: ., bookauthoratk, bookcentury1900, bookdecade1900, booksubjectbotany
