581 



A NOTE ON THE SLIDES OF FISSIDENTACEAE IN 



THE Q.M.C. CABINET. 



By G. T. Harris. 



(Read May 'loth, 1915.) 



Communicated by Clarence J. H. Sidwell, F.R.M.S. 



In Dixon's Student's Handbook of British Mosses the Fissi- 

 dentaceae of Great Britain comprise fourteen species and about 

 five well-marked varieties. Of these fourteen species eight 

 are represented in the Cabinet of the Quekett Microscopical 

 Club, and of these eight four at least are rare, and several very 

 rare. Fissidens exilis is the smallest of our native species and 

 is often found accidentally among some gathering of quite 

 another moss when examination takes place at home. There 

 is no difficulty in recognising it owing to its minute size and 

 non-bordered leaves. Fissidens viridulus is very slightly larger 

 than exilis, but has the leaves distinctly bordered with a narrow 

 cartilaginous border, which is usually lost at the apex ; the 

 variety Lylei, however, may be confused with exilis, as it is 

 very minute and has no border except on the sheathing laminae, 

 indeed it has been made a separate species by some authors. 

 It has been proposed to unite the species viridulus, pusillus, and 

 incurvus under one specific type, as intermediate states are 

 often met with. Fissidens incurvus var. tamarindifolius also 

 at one time had specific rank, but is now generally accepted as 

 a variety of incurvus. It is usually found sterile and has a quite 

 distinct facies when growing, that readily assures it recognition. 



