GRIMMIA. 147 



23. Grimmia elongata Kaulf. (Tab. XXIII. E.). 



In tall lax tufts, 1-2 inches high, with long slender stems, 

 decumbent at base and often denuded, frequently half buried in 

 sand, of a dull green or reddish-brown colour. Leaves crowded, 

 appressed and slightly twisted when dry, small, £-$ line long, 

 narrowly oblong or linear, carinate-concave, one margin slightly 

 recurved, thickened above ; nerve narrow but distinct ; lower 

 leaves muticous, only the upper with a very short, narrow hyaline 

 point, or even a few cells only diaphanous. Cells of mid-base 

 elongate-rectangular or linear, with smooth walls, a few rows 

 towards margin sinuose, yellow, slightly incrassate, about two rows 

 at margin shorter, broader, hyaline, forming a border extending a 

 considerable distance up the leaf ; above, the cells become chloro- 

 phyllose, very sinuose, rectangular, slightly shorter towards apex, 

 but always longer than broad, elliptic-rectangular. Seta short, 

 capsule exserted, small, oval, smooth, not contracted at the mouth ; 

 lid conical, obtuse ; calyptra cucullate, lobed at the base ; peristome 

 teeth broad, almost entire. Dioicous. 



Hab. Damp crevices of alpine rocks. Very rare and sterile. Clova (Fergusson) ; 

 Cumberland Mountains (Binstead). 



The British form is stunted, in dense tufts less than an inch high. The very 

 short hair-points and the reddish brown colour give the plant a very different aspect 

 from most of the species of the genus ; and the form and structure of the leaves easily 

 determine it. Perhaps G. torquata comes nearest to it in the leaves, but the basal 

 areolation differs, and the habit is quite distinct. 



24. Grimmia atrata Mielich. (Tab. XXIII. F.). 



Tall, 1-2^ inches high, densely tufted, yellowish green above, 

 black below. Leaves solid, about 1 line long, variously spreading 

 and curved, twisted when dry, lanceolate, gradually narrowing 

 front base to apex, obtusely pointed ; without hyaline points ; 

 nerve strong, broad, rather prominent at back ; margin very 

 slightly and irregularly recurved, thickened from near the base 

 upwards ; cells at angles and for a short distance up the margins 

 lax, quadrate, hyaline, in mid-base variable, rather short, slightly 

 sinuose, soon becoming sinuosely rectangular, above distinct, in 

 upper part of leaf small, sub-quadrate, incrassate. Capsule erect 

 or slightly oblique on a rather long seta, oval-oblong, thick-walled ; 

 lid shortly rostellate, obtuse; calyptra mitriform or sub-cucullate. 

 Dioicous. 



Hab. Wet alpine rocks. Rare. Fr. autumn. 



