LESCUR^A. 393 



patches. Leaves erecto-patent, closely imbricated when dry, 

 very small, about |-line in length, narrowly lanceolate, tapering, 

 hardly plicate, entire or feebly denticulate, margin reflexed for 

 the greater part of its length ; nerve strong, thick, reaching the 

 base of the acumen ; upper cells shortly rhomboid, lower rather 

 laxer, hexagonal-rectangular, at margins shorter, at basal angles 

 quadrate. Paraphyllia numerous, small, narrow, oval or lanceo- 

 late. Seta short, capsule elliptic-oblong. Peristome teeth 

 narrow, linear. 



Var. f3. saxicola B. & S. (Lescursea saxicola Milde). More 

 robust, leaves wider, often subsecund, ovate-lanceolate, more 

 concave, slightly plicate, denticulate above. 



Hab. Stems of shrubs and trees in mountainous countries. The var. j3 alone 

 found in Britain, on alpine rocks ; Ben Lawers ( West). Fr. spring. 



The var. saxicola alone has been found, in one locality only. It is by some 

 authors considered a separate species, but apparently on slight grounds ; leaves 

 varying in width and in other characters may be found on the same plant. The 

 slender, almost filiform stems, and minute leaves with long nerve have some resemb- 

 lance to Pseudoleskea atrovirens, but the colour is much paler, the cells smooth, and 

 the capsule erect. The long stout nerve and short cells taken in conjunction will 

 easily separate it from any other plant that might be confused with it ; Brachythecium 

 populeum might perhaps be so confused, but has a thinner nerve, larger leaves, and 

 the marginal areolation quite distinct. 



107. ISOTHECIUM Brid. (emend. B. & S.). 



Primary stem stoloniform, secondary erect, more or less 

 dendroid, branches somewhat tufted, curved in one direction, 

 often flagelliform. Leaves more or less ovate-oblong, single- 

 nerved half-way at least; areolation smooth or somewhat 

 papillose at back, shortly linear-vermicular or rhomboid, at 

 angles distinct, rectangular or ovate. Dioicous. Capsule erect, 

 symmetrical or almost so, oblong. Inner peristome with a 

 moderately long basal membrane, cilia short, rudimentary. 



There is little but the erect, symmetrical capsule to separate 

 the genus, as defined by Bruch and Schimper, from Eurhynchium, 

 and it is somewhat doubtful how much value ought to be 

 attributed to that character. On the other hand, there are a 

 number of North American species which naturally fall under this 

 genus, most of which agree also in having the leaves more or less 

 papillose, and this would appear to afford an additional ground 

 for retaining Isothecium as a separate genus. 



