108 



THE OPHIOGLOSSALES 



much as they are in Botrychium. In one small root, however (fig. 80, D), the apex 

 was occupied hy three cells which together formed a triangular group, but these 

 cells were of about equal size and it is not at all certain that the triangular cell v 

 was really the apical cell. 



In longitudinal sections of the larger roots there is a close approximation of 

 the condition found in the Marattiace;e. There is probably still a single apical cell, 

 as there is in the early roots of the Marattiaceae, but this cell is somewhat truncate 

 below (fig. 54, B) and in a cross-section, taken from a tetrarch root, a single apical 

 cell was not clearly to be distinguished. The lateral segments are veiy large and 



Fig. 80. 



A. Section of pentarch root of Hclminthostaclns. X20. C. Root of young sporophyte, with tetrahedral apical cell. X150. 



B. Part of the vascular bundle. X150. D. Root of an older sporophytr, with truncate apical cell, x. 



there are cut off from them cells which contribute to the root cap. In short, the 

 apical growth in the later roots of Helminthostachys is evidently more like that of 

 Dmiiea, for example, than it is like Botrychium. 



THE SPORANGIOPHORE OK THE OPHIOGLOSSALES. 



In all of the Ophioglossaceae the sporophyll, as we have seen, consists of two 

 parts, the fertile spike (or sporangiophore) and the sterile lamina. 1 here is very 

 great diversity of opinion as to the real nature of the sporangiophore. The earlier 

 views were strongly influenced by the old theory that the sporangial parts were 



