48 



THE OPHIOGLOSSALES 



All of the organs of the young sporophyte arise, as Jeffrey showed, from the 

 epibasal region, and in this respect Botr\chium virginianitm agrees with the Marat- 

 tiaceae and with Ophtoglossum. According to Bruchmann, the embryo in B. lunaria 

 remains quite undifferentiated up to the time it breaks through the calyptra, even 

 the root apex being unrecognizable at this time. It is therefore impossible to say 

 what relation the organs of the young sporophyte bear to the primary divisions of 

 the embryo. 



.cot 



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 apex. 



Fig. 33. — Two sections of an oXdf^r cmhryool Botrychium virgintanum^ cut in the 



plane of the cotyledon. 



J/, stem apex; /^, root; /, foot. Xioo. 



