252 HISTORY OF BRITISH FERNS. 



stems. These are quite dissimilar in their appearance, 

 some being short, quite simple, and terminating in a cone- 

 like head of spore-cases ; others being without fructification, 

 taller, and producing several whorls of long, crowded, slen- 

 der branches ; whilst a third kind, of 'common though not 

 constant occurrence,' produce whorls of branches and cones 

 also. In the production of these three kinds of stems it 

 serves to connect, through E. syhaticum, that group in 

 which the fertile and barren stems are successive and 

 altogether unlike, with that in which any of the stems 

 inJitTerently — at least as to external appearances — bear the 

 fructification, all being of similar habit. 



The fertile stems grow about six inches high, and are 

 quite branchless ; they are of a pale yellowish-green, having 

 numerous joints, the large loose funnel-shaped sheaths 

 produced at these points almost covering the stem, as 

 usually described and figured ; but in our specimens they 

 are much less crowded, a space of from half an inch to an 

 inch occurring between the adjoining sheaths. These 

 sheaths are still paler-coloured than the stem, often almost 

 white, with a dark ring below the teeth, which are awl- 

 shaped, pale-brown, with pale-coloured membranous mar- 

 gins ; the teeth are about twenty — from twelve to twenty — 



