Grimmiace^.] 4 [Grimmia. 



In both divisions transverse sections of the leaves are of the greatest 

 importance in showing their structure, and it will thus be seen that the 

 margin is often thickened by the cells being in two layers, though, in some 

 cases, it is only a single row of cells which is double. Chalubinski's " Grim- 

 mieffi Tatrenses " is a splendid monograph of the species found in that part 

 of the Carpathians. 



Stihf. I. GRIMMIE^. Densely tufted, pulvinate, or taller and 

 csespitose, dichotomous ; leaves ovato-lanc, opake, often hair-pointed, upper 

 cells minute, rounded or hexagonal, smooth or weakly papillose, lower 

 elongated or linear and sinuose. Calyptra mitraeform, rarely cucullate, 

 smooth or sometimes plicate. Caps, erect, on a straight or arcuate seta ; 

 peristome simple, very rarely none ; teeth lanceolate, papillose, entire or 

 lacerate or lacunose or in filiform segments. 



I. GRIMMIA Ehvh. 



Beitr. i, 176. (1781). 



Mosses growing in small cushions or tufts, generally rooting only 

 at base, innovating below the fertile apex. Leaves crowded in 5 — 8 

 rows, patent, lanceolate, usually passing into a white hair, terete- 

 nerved, with the margin narrowly incrassate-limbate, entire, very rarely 

 eroso-denticulate at point, minutely papillose, toward apex quadrato- 

 or hexagono-areolate, opake and often bistratose, at base wider, 

 hexagono-rectangular, linear, sinuoso- or tuberculoso-linear, towards 

 mai'gin rectangular. Calyptra small conic lobate, covering only the 

 operculum, or larger mitraeform and lacerate at base, lobato-cucullate 

 or cucullate, smooth or with a rough beak. Capsule erect, cernuous or 

 pendulous, peristome very rarely none, simple, teeth 16, transversely 

 articulated, lanceolate, entire, cribrose, cleft or with filiform legs, 

 papillose, purple, hygroscopic. Inhabiting rocks and stones. — Der. 

 after J. F. C. Grimm, a physician of Gotha. 



This genus comprises about 150 species, varying greatly in size from 

 little dense cushions one-third of an inch high, to the great mats of 

 G. hypnoides, whose stems attain a length of 8 inches. The dingy colour of 

 the leaves, tipped with long or short white hairs is their most striking 

 feature, and it will be noticed the latter is not due to the excurrent nerve, 

 but to absence of chlorophyl from the leaf point. 



Clavis to the Species. 



Sect. I. SCHISTIDIUM. Capsule immersed, wide mouthed ; lid 

 falling with the columella attached. 



Upper leaves hyaline at point, margins revolute. 



In small dense cushions, soft, lurid green. conferta. 



In laxer cushions, more robust, coarse, fuscescent. apocarpa. 



All leaves muticous, margins plane. maritima. 



