GRIMMIA. 139 



* Grimmia Miihlenbeckii Schp. (Tab. XXII. C). 



Very near G. trichophylla, and by some authors considered a 

 variety only, differing as follows : — Rather more robust than the 

 usual form of that plant, leaves more strongly keeled with the 

 nerve more prominent at back, hair-point strongly denticulate or 

 spinulose ; the margins less recurved ; the capsule smaller, 

 shorter, smooth or very indistinctly striate when dry. These 

 characters are, however, subject to much variation, whether in G. 

 trichophylla or G. Miihlenbeckii, and it appears to be a rule that 

 in G. trichophylla the shorter the capsule the less plicate it 

 becomes, while the greater or less denticulation of the hair-point 

 is equally unimportant, typical specimens of G, Miihlenbeckii as 

 regards the fruit sometimes having the hairs only faintly 

 denticulate. It usually grows- in more compact tufts, not in loose 

 wide patches as does G. trichophylla, and is more at home at 

 high altitudes, whereas the latter prefers subalpine situations and 

 more exposed rocks. 



Hab. Siliceous rocks, usually on mountains. Very rare. Ballater. Kynance 

 Cove. Fr. summer. 



11. Grimmia subsquarrosa Wils. (Tab. XXII. D.). 



In small lax tufts, hardly one inch high, dull green above, 

 blackish below; somewhat resembling G. trichophylla ; leaves 

 crowded, gradually longer upwards, forming a slight comal tuft 

 at the apex of the slightly curved branches, the lower patent, 

 the upper squarrose, when dry erect and appressed ; broader than 

 in the above species, and shorter (§-f lines), margin recurved ; 

 lower muticous, upper with a shorter, roughish hair, about \ length 

 of the leaf ; basal cells short, wide, rectangular, somewhat hyaline, 

 thin-walled, not sinuose, about \\ times as long as wide, a few 

 near the nerve occasionally longer and narrower ; in the upper 

 part of the leaf minute, sub-quadrate or irregular, obscure, often 

 incrassate. I have seen no description of the fruit ; the capsules, 

 in the only fertile specimen I possess are old, dark coloured, 

 resembling G. trichophylla but smaller, on a shorter seta, bluntly 

 striate. Dioicous. 



Var. (3. edinensis Braithw. (G. edinensis Ferg.). Very 

 short, black, in dense cushions ; leaves shorter, less concave- 

 carinate, less squarrose. 



Hab. Siliceous rocks, rare, or overlooked. The var. j8, Arthur's Seat 

 (Fergusson). Fr, very rare. 



