. Carnegie Institution of Washington publication. 154 THE MARATTIALES in his earlier studies of this plant failed to find a single initial cell; however, in a more recent paper (farmer 3) he has decided that a single apical cell is present in the young sporophyte of Angiopteris, and he gives figures of this. In longitudinal section (fig. 134) the apical cell appears oblong, with a markedly truncate base, while in transverse section it is imperfectly triangular in outline. I he apical cell of the stem in Kaulfussia (fig. 136, C) is usually somewhat broader than it is in Angiopteris, and closely
. Carnegie Institution of Washington publication. 154 THE MARATTIALES in his earlier studies of this plant failed to find a single initial cell; however, in a more recent paper (farmer 3) he has decided that a single apical cell is present in the young sporophyte of Angiopteris, and he gives figures of this. In longitudinal section (fig. 134) the apical cell appears oblong, with a markedly truncate base, while in transverse section it is imperfectly triangular in outline. I he apical cell of the stem in Kaulfussia (fig. 136, C) is usually somewhat broader than it is in Angiopteris, and closely resembles that of Ophioglossum moluccanum. It has a broadly truncate base and is somewhat narrowed above. In transverse section it approaches the triangular outline of the apical cell in Ophioglossutiu but the seg- mentation is less regular and in this respect it is not unlike that of Angiopteris. The stem apex was examined in three species of Datura, all of which seemed to agree. Fig. 137.—Kautju A, B. Two transverse sections of a young sporophyte, above C. Transverse section of petiole of cotyledon. Xoo. level of stem apex, show'ng closed sheath formed by D. Vascular bundle of cotyledon, more enlarged, base of cotyledon. I1, second leaf. X50. E. Second leaf. closely in the form of the apical cell, which is much more definite in Dancea than it is in any of the other genera. Brebner's account and figure of the apical cell in D. simplicifolia agree closely with my own preparations of D. ellipttca, D. jenmam, and D. jamaicensts. The apical cell (fig. 140, A), seen in longitudinal section, is very deep and, unlike that of the other genera, is not usually, at least, truncate below, but pointed, so that it closely resembles in form that of Botrychium or llelmmthostachys. In transverse section it also usually appears triangular, so that it is tetrahedral like that of Botrychium. While the segmentation is somewhat less regular than in Botrychium, nevertheless the limits of the youn
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