BRITISH FERNS. 7 



AsPLENiUM (Smith). — Thecse in elongate and straight masses. British 

 species, 1. Lanceolatum ; 2. Adiantum-nigrum ; 3. Ruta- 



MURARIA ; 4. SePTENTRIONALE ; 5. MaRINUM ; 6. ViRIDE ; 



7. Trichomanes. Exotic species very numerous. 



ScoLOPENDRiUM (Smith). — Thecae in elongate and straight lines, always in 

 pairs, the two indusia meeting between them, and at first appearing 

 but as one indusium. British species, 1. Vulgare. Exotic 

 species very few. 



Family V. — GrammitidecB. — Thecae in an elongate mass, uncovered by any indusium. 



Grammitis (Hooker). — Lateral veins unconnected at their extremities. 

 Exotic species, 1. Serrulata ; 2. Myosuroides ; \d. Setosa, and 

 many others. 



Ceterach (Loudon). — Lateral veins anastomozing. British species, 

 1. Officinarum. Exotic species, only one or two known. 



Section II. — Filices annulatje desciscentes. — Thecse attached in a receptacle 

 situated on the margin of the frond. 



Family VI. — Hymenophyllacece (including the entire section). 



Trichomanes (Smith). — Marginal receptacle furnished with an exserted 

 bristle-like appendage. British species, 1. Speciosum. Exotic 

 species very numerous, and of great beauty. 



H YMENOPHYLLUM (Smith). — Marginal receptacle unfurnished with the bristle- 

 like appendage. British species, 1. Tunbridgense ; 2. Wilsoni ; 

 Exotic species unknown to me. 



FILICES EXANNULAT^. 



The thecae are unprovided with the elastic marginal ring. 

 Family VII. — Osmundacece. — Vernation circinate and rachis solid, as in the Filices 

 annulatas. 



Osmunda (Smith). — Thecse in a branched spike terminating the frond. 

 British species, 1. Regalis. Exotic species very numerous. 

 Family VIII. — Ophioglossacea. — Vernation straight, and stem hollow. 



Botrychium (Smith). — Thecse in a branched spike attached to a divided 

 frond. British species, 1. Lunaria. Exotic species numerous. 



Ophioglossum (Smith). — Thecae in a straight club-shaped spike attached 

 to an undivided frond. British species, 1. Vulgatum. Exotic 

 species few. 



\* The generic and specific names printed in small capitals are employed in the 

 following pages ; those in italics are considered either synonymous or exotic, and are 

 not employed. The name following the genus is that of a British author who 



