XIX] 



ANATOMY 



63 



a further and variously cut development of the plan thus initiated (Fig. 358). 

 But in all the species of Ophioglossum the sterile blade shows a closed 

 reticulum, certain veins of which lying near to the centre are thicker, and 



Fig. 357. .-i = cotyledon of Botrychium virginiaimm ( x 4). 5= juvenile leaf of Hclminthostachys, 

 probably an actual cotyledon: from the collection of Dr Lang (X4). Here the ontogeny starts 

 from a stage which appears relatively late in the series of Osiniinda (Fig. 416), or of Anemia. 



Fig. 35^ 



^ = apex of adult leaf of Botrychium Virginia)! 11 ni ( x 2). i5 = distal end of a leaf of 

 Botrychium jenDiani (x 4), showing a more fully webbed condition. 



