156 VASCULAR PLANTS. 



let, solitary in the disk of the laciniae. Indusi- 

 um hyaline, laterally affixed, free towards the 

 margin of the frond. It . 



ORDER Xim. STIPULATED- 



Isosporous. Leaves stipulate. 



Family CXIV. Ophioglosseae. 



Sporangia capsular, developed in the paren- 

 chyma of half the frond. Vernation not cir- 

 cinate. 



l. Botrychium, Swartz. 



Fertile segment of the frond a compound 

 spike. Sporangia distinct, glabrous, distich- 

 ous, nearly 2-valved. 2f . 



ORDER XLTV. EQUISETACED. 



Isosporous. Stem articulate; internodes sur- 

 rounded by sheathing whorls of scarious leaves. 

 Sporangia on the under side of verticillate-pel- 

 tate receptacles, forming a terminal spike. 

 Spores oo , each furnished with 2 elaters. 



1. Equisetum, L 



Only genus. Characters of the order. 



