94 ON THE CLASSIFICATION OF FERXS. 



OSMTJNDACE^E. 



Fronds circinate, sori destitute of an elastic ring, 

 and bursting vertically by two regular valves. 



14. OSMUNDA. The only genus. 



OPHIOGLOSSACELE. 



Young fronds folded up straight, the sori without 

 an elastic ring, and 2-valved. 



15. BOTRYCHIUM. Sori in irregularly branched 

 dusters on a separate branch of the frond. 



16. OPHIOGLOSSUM. Sori sessile, in Z-ranked simple 

 spikes on a separate frond. 



In order to facilitate finding the name of a fern, 

 we add the following analytical index, for the general 

 plan of which we are indebted to Mr. Bentham's 

 admirable " Handbook of the British Flora."* 



( Fructification in a terminal spike or panicle. The frond 



either leaf-like, or bearing a leaf in the lower part .... 2 



, J Fructification in a little cup or involucre at the edge of the 



1 | frond 4 



Fructification on the back or under-side of some or all the 

 I fronds 5 



f Fronds twice-pinnate, usually two or more feet high, the 

 fructification forming a panicle at their extremity. 



2 { OSMUNDA. 

 j Fronds stem-like, not 6 inches high, with a terminal spike 

 t. or panicle 3 



( Spike simple. Leaf entire OPHIOGLOSSUM. 



( Spike branched into a panicle. Leaf pinnate. BOTEYCHIUM. 



C Fronds numerous, scarcely 2 inches high, pinnate, with few 



deeply-lobed segments. Involucre ovate, 2-lobed. 

 4 -i HYMEXOPHYLLUM, 



Fronds 6 or 8 inches high, two or three times pinnate, with 

 L crowded segments. Involucre cup-shaped. TBICHOMANES. 



Published by Lovell Reeve, Henrietta-street, London. 



