444 



OPHIOGLOSSALES 



as a storage-body. The leaves are inclined right and left of the mediai 

 line in acropetal succession, one as a rule but sometimes more rising 

 above ground in each season. The leaf shows a similar stipular structui 

 to that seen in others of the family : upwards it consists of a stout petiole, 

 with a large lamina usually ternate, each of the divisions being again 

 subdivided. From their point of junction rises the fertile spike, which 

 adaxial as in other Ophioglossaceae. But the chief distinctive point is in 

 the structure of it ; for numerous sporangiophores each bearing several 

 sporangia are disposed in dense serried ranks right and left that is, in 

 positions corresponding to the rows of sporangia in Ophioglossum (Figs. 

 244 and 83). 



-R 



FIG. 243. 



H elminthostachys zeylanica, Hook. Rhizome. Natural size, /^flap; .ft = root; 

 Z- = leaf ; P petiole ; LS leaf scar. (After Farmer and Freeman.) 



The spike of Helminthostachys not uncommonly shows irregular accessory 

 branchings, such as those seen on Figs. 239 L, M. These may be combined 

 as in Botrychmm with correlative vegetative growth where sporangia are 

 absent (Fig. 239 N), while the details of these show in a beautiful manner 



becomes elongated as an internode : the initial cell is gradually overarched by upgrowth 

 of the surrounding tissue, while by its sunken position it remains in close relation to the 

 vascular system of the rhizome. The single cell meanwhile divides into a cell-group, and 

 may continue to grow, forming a leafy bud. Bruchmann compares this bud-formation 

 with that of lateral buds in many Ferns. The comparison may also be made with the 

 lateral buds of Equisetum : the deeply sunken position compares not only with these, but 

 more particularly with that seen in the tuber of Phyttoghssum ; in fact, the sunken 

 character in the Ophioglossaceae has probably, as in these plants also, been assumed in 

 relation to the underground habit. 



