48 



I II I orilMic.l.n.ss VLES 



Ml ol tin organs cil the young sporophyte arise, .is Jeffrey showed, from the 

 epibasal region, and in tins respect Botrychium virginianum 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 mot apex being unrecognizable at this time. It is therefore impossible to say 

 what nlation the oil;. ins ol the young sporophyte bear to the primary divisions of 

 tin embryo. 



cot 



st xc^sr^>. 



Fig. 32. — Three sections of an older embryo of Botrychium virginianum, cut transverse to long axis of embryo. 

 b b, basal wall; /, f^ot; r, root; rf,stemapex; eo/, cotyledon. 200. 



In B. virginianum traits of the quadrant formation are still evident at a com- 

 paratively latr 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 (). vulgatum, the root is especially conspicuous and 

 reaches a large size, while tin stem apex and cotyledon are still inconspicuous. 

 Indeed, in B. lunaria, according to Bruchmann, no trace ol either stem apex or 



D >i vlcdoti can he made out 

 until the root has broken 

 through the calyptra. At 



this stage ( fig. 36, C, D) 

 the embi vo of 11. lunaria 

 bears a striking resem- 

 blance to that of Ophto- 

 glossum vulgatum. 



It was found bv Jef- 

 1 1 1 \ m B . virginianum 

 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. ^2 shows 

 three sections of a series 

 taken from an embryo of 

 about the age of [effrey's fig. 4.6. I his embryo wascut transversely to its long axis, 

 and the root apex is thus seen in cross-section. I he 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. .ji, II 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. }2, C, shows the section passing through the stem apex. 



It'.;, I '' ium virginianum, cut in the 



('Line of the cotyledon. 



st, stem apex; '.root; /, foot. Xioo. 



