210 TORTULACEjE. 



The plane-margined leaves, slightly wider and more distinctly mucronate, and 

 the larger spores, are really the only distinguishing characters by which this species 

 may be known from W. viridula. According to Husnot, whose measurements of the 

 spores is confirmed by my own observations, the statement made by Bruch and 

 Schimper in the Bry. Eur. , and copied by Wilson, that they are 2 or 3 times as large 

 as in W. viridula is inaccurate, and is not borne out by Bruch's own specimens. 



C. EUCLADIUM. 



Plants usually taller; leaves more rigid and fragile, with a 

 stout nerve, less crisped when dry. Rupestral. Dioicous. 

 Capsule exserted, gymnostomous or peristomate. 



10. Weisia tenuis C. M. (Mollia tenuis Lindb., Braithw. 

 Br. M. Fl. ; Gymnostomum tenue Schrad., plur. auct. ; Gyroweisia 



tenuis Schp., Syn.) (Tab. XXXI. C). 



Very short, in wide mats, bright green above, hardly 2 lines 

 high. Leaves very small, about i line long, erecto-patent, 

 slightly recurved, when dry erect, hardly twisted, rigid, fragile ; 

 ligulate, rounded and obtuse at apex, margin plane, often 

 crenulate with projecting papilla? ; nerve rather strong, ceasing 

 below apex. Basal cells rectangular, hyaline, j-6 times as long 

 as broad, above shortly rectangular, at apex sub-quadrate and 

 irregular, papillose, rather thick-walled, distinct ; perichaetial 

 bracts larger, wider and sub-sheathing. Capsule on a short very 

 slender seta, gymnostomous , small, narrowly oblong, red at 

 mouth ; annulus broad, persistent ; lid very short, conical- 

 acuminate. Male plants very short. 



Hab. On inclined faces of sandstone or calcareous rocks ; not common. Fr. 

 summer and autumn. 



W. tenuis is known from all the other species (except W. calcarea) by the dwarf 

 plants in neat patches of a deep green, and the small, ligulate leaves very rounded 

 and obtuse at apex ; the leaves in W. calcarea are more frequently narrowed and 

 shortly pointed, the basal cells much shorter, the upper more obscure, the lid .longer, 

 and the whole plant as a rule taller. The period of fruiting appears to be extended 

 and variable in W. tenuis. 



11. Weisia calcarea C. M. (Gymnost. calcareum Nees & 

 Hornsch., Schp. Syn. ; Mollia calcarea Lindb., Braithw. Br. 



M. Fl.) (Tab. XXXI. D.). 



Resembling the last species but usually taller, J— J inch, 

 stems slender, branched, very densely tufted, bright light green. 



