. The Eusporangiatae; the comparative morphology of the Ophioglossaceae and Marattiaceae. Ophioglossaceae; Marattiaceae. Fig. 32.—Three sections of an older embryo of Botrychium virgmianum, cut transverse to long axis of embryo. b b, basal wall; /, foot; r, root; si, stem apex; col, cotyledon. X2CX3. In B. virgintanum traces of the quadrant formation are still evident at a com- paratively late stage, and there seems no reason to doubt the correctness of Jeffrey's conclusion as to the epibasal origin of both the root and the cotyledon. As in Ophtoglossum pendulum and O. vulgatum, the root is es
. The Eusporangiatae; the comparative morphology of the Ophioglossaceae and Marattiaceae. Ophioglossaceae; Marattiaceae. Fig. 32.—Three sections of an older embryo of Botrychium virgmianum, cut transverse to long axis of embryo. b b, basal wall; /, foot; r, root; si, stem apex; col, cotyledon. X2CX3. In B. virgintanum traces of the quadrant formation are still evident at a com- paratively late stage, and there seems no reason to doubt the correctness of Jeffrey's conclusion as to the epibasal origin of both the root and the cotyledon. As in Ophtoglossum pendulum and O. vulgatum, the root is especially conspicuous and reaches a large size, while the stem apex and cotyledon are still inconspicuous. Indeed, in B. lunaria, according to Bruchmann, no trace of either stem apex or cotyledon can be made out until the root has broken through the calyptra. At this stage (fig. 36, C, D) the embryo of 5. lunaria bears a striking resem- blance to that of Ophto- glossum vulgatum. It was found by Jef- frey in B. virgtnianum that the stem initial was developed before the co- tyledon could be seen, but I have failed to verify this in the specimens I have examined. Fig. 32 shows three sections of a series taken from an embryo of about the age of Jeffrey's fig. 46. This embryo was cut transversely to its long axis, and the root apex is thus seen in cross-section. The root here probably comprises the whole of one of the epibasal quadrants, from the other of which, or from part of it, perhaps a single octant, the stem apex and cotyledon arise in close proximity. It is probable that part of this quadrant goes to form the "suspensor," or that epibasal tissue which is not concerned in the formation of the young organs of the embryo. Fig- 32. B shows a section passing through the young cotyledon, whose single apical cell is already differentiated. This in section is triangular, and the cell is probably of tetrahedral shape. Fig. 32, C, shows the section passing through the stem
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