THE ADULT SPOROPHYTE 



101 



the texture of the leaf is soft and fleshy, like that of Ophioglossum, but in B. virgim- 

 anum it is thin and membranaceous, like that of many true ferns. In B. lunaria 

 (fig. 72, D) the venation comes nearer to that of Ophioglossum than is the case in 

 the larger species. The fan-shaped leaflets have no midrib and the veins branch 

 dichotomously from the base of leaf, radiating from this point in the manner de- 

 scribed as "cyclopterid." In the larger species the leaflets have a distinct midrib 



Fig. 73. 



A. Rhizome of a strong plant of Botrychium virginianum. Xi. The base of the expanded leaf is cut away. 



B. Section of the terminal bud. si, stem apex. 1, 11, in, the three youngest leaves. X2.66. 



C. Section of petiole, enlarged. 



D. Section of rhizome; p, pith; m, medullary rays; *,xylem; ph, phloem; c, cambium; sh, endodermis. X16. 



Fig. 74. 



A-G. A series of sections of the sporophyll of Botrychium lanuginosum Wall. C is reversed in 



position. G, section of peduncle. 

 H. Section of the petiole of the cotyledon of B. virginianum. i, i, lacuna 1 . 



and the forking veins are attached to this laterally (fig. 72, E). The type of B. 

 lunaria is without question the more primitive, and were the ends of the veins united 

 so as to inclose areoles there would be exactly the same type of venation as is found 

 in Ophioglossum. 



In Eubotrychium the anatomy of the leaf is almost exactly like that of Ophio- 

 glossum, stomata being developed upon both sides of the leaf; the mesophyll is 

 composed of absolutely similar cells throughout and the vascular bundles running 



