. The Eusporangiatae; the comparative morphology of the Ophioglossaceae and Marattiaceae. Ophioglossaceae; Marattiaceae. 164 THE MARATTIALES to demonstrate an external endodermis in the stem bundles o(Jngwpterts,Marattia, and Kaulfussia, and presumably similar treatment would show its presence in the young s'em of-Dan^fl. It is evident that we can not speak of the young sporophyte in Daneea jamat- censis as possessing in its early stage a " protostele," or "haplostele," to use Brebner's terminology, unless we choose to call the single leaf trace of the cotyledon a protostel
. The Eusporangiatae; the comparative morphology of the Ophioglossaceae and Marattiaceae. Ophioglossaceae; Marattiaceae. 164 THE MARATTIALES to demonstrate an external endodermis in the stem bundles o(Jngwpterts,Marattia, and Kaulfussia, and presumably similar treatment would show its presence in the young s'em of-Dan^fl. It is evident that we can not speak of the young sporophyte in Daneea jamat- censis as possessing in its early stage a " protostele," or "haplostele," to use Brebner's terminology, unless we choose to call the single leaf trace of the cotyledon a protostele. Just so soon as the two first leaf traces unite, the axial vascular bundle of the young sporophyte has two quite independent xylems. Figure 147 is a longitudinal section of a sporophyte of D. elliptica, slightly older than that of D. jamaicensis shown in fig. 138. The second leaf (/') had already begun to develop the lamina, whose apex was forked so that there were two veins present. A longitudinal section of one of the two leaf lobes is shown in D. The stem apex closely resembles that of D. jamaicensis, the apical cell having much the same form and size. The stem apex does not lie in the same plane as the leaf traces. B Fig. 147.—Danaa elliptica. A. Nearly median section of a young sporophyte, showing origin of second root, r^. X35. B. Central region. X150. C. Median section of second leaf. D. Apex of second leaf. X150. E. Stem apex, X150. ^35- and hence does not show in the figure, which is a section passing directly through the leaf traces. This plant showed very clearly the very earliest stage of the second root (fig. 147, A, r). The apical cell of the young root is cut out from one of the cells of the parenchyma below the stem apex, lying almost exactly half-way between the two primary leaf traces. Only a single segment had been cut off from the apical cell in this case and both the apical cell and this primary segment were easily dis- tinguished from the surrounding
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