CRYPTOGAMIA. 



736. HYMENOPHYLLUM. Sorus marginalis, recepta- 

 culo cylindraceo insertus. Indusium bivalve, sorum 

 includens. 



651 



V. HYDRO PTERIDES. 



737. ISOETES. Capsitla membranacea; non dehiscens, 



frondis basi immersa, l-locularis. 5t?7ni«a angulata, 

 receptaculis pluribus filiformibus inserta. 



738. SALVINIA. Indusia imbricata, connata, capsnlam 



unilocularem mentientia, Semina receptaculo cen. 

 trali inserta. 



739. AZOLLA. Capsula unilocularis, radicalis, globosa, 



polysperma. 



I. GONOPTERIDES. 



713. EQUISETUM. Gen.pLlQlA. 



1. E. caulibus sterilibus simpliciter ramosis, ramis scabrins- arvense. 



culis tetragonis, fructificationibus simplicibus, vaginis 



cylindraceis inciso-dentatis, denlibus acatis. Willd, 



enum. 1005. IFiUd. sp. pi. 5. p. 1. 

 Icon. Schkuhrjillc. t. iQj. 

 In low and sandy fields : Pensylvania and Virginia. %. 



April, May. v. v. 



2. E. caulibus sterilibus fructificantibusqueduplicato-ramo- sylvaticuw. 



sis, ramis scabriusculis deflexis tetragonis, ramulis 



subtriquetris. Willd. enum. 1065. IFilld. sp. pi. 5. 



p. 3. 

 Icon. SchkuKr fillet. \QQ. Fl. dan. l]82. 

 In low shady woods : New York to Virginia. 1/ , April 



— June. V. V. 



3. E. caulibus subramosis, ramis subquaternis tetragonis uUginosum. 



glabris, spica cylindracea terminali. — Willd. sp. pi. 5. 

 p. 4. 

 In swamps : New York to Virginia. % . May, v. v. 

 Resembles E. limosum. 



4. E. caulibus simpliciter ramosis glabris sulcatis, ramis palustre. 



pentagonis apice spiciferis. Willd. enum, 1005. 

 Willd. sp. pi. 5. p. 5. 



