VASCULAR PLANTS. 153 



parietal: macrosporangia always 1-spored. Ver- 

 nation circinate. 



l. Marsilaea, L. 



Macro- and microsporangia in the same spor- 

 ocarp. 



U . fronds petiolate, 4-foliolate. 



Family cxii. Salviniaceae • 



Sporocarps 2 — oo, on the same petiole (trans- 

 formed half of leaf). Macro- and microspor- 

 angia in distinct sporocarps. Vernation not 

 circinate. 



l- Azolla, Lam. 



Sporocarps in pairs. Macrosporangia 1-spor- 

 ed. Aquatics, moss-like, floating, green or pur- 

 plish. 



ORDER XL.H FILICES. 



Isosporous. Sporangia formed from the epi- 

 dermis, bursting by an elastic ring. Fronds 

 without stipules. Vernation circinate. 



Family cxiii. Polypodiaceae. 



Sporangia hypophyllous, somewhat globular. 

 Ring vertical. 



1. Gymnogramme, Desf. 



Sori linear, placed on branching primary 

 veins. Indusium 0. If. 



