138 GRIMMIACE/E. 



slightly contracted at the mouth ; lid short, obtuse, mamillate. 

 Annulus narrow. Peristome pale red, more distantly and 

 distinctly barred. 



Hab. Calcareous walls and rocks ; not common. Fr. spring. 



Of a rather duller colour than the last species, and differing markedly in the 

 characters italicised above. Without microscopic examination the var. obtusa of that 

 species might easily be taken for it, and the two occasionally grow together. The 

 basal cells will, however, aid in separating them under the microscope. 



10. Grimmia trichophylla Grev. (Tab. XXII. B.). 



In loose wide patches, grey or yellowish green, \-\ inch high. 

 Leaves narrow and elongated, linear-lanceolate to broadly 

 lanceolate, tapering to a long point, erecto-patent, when dry 

 appressed and slightly twisted, the lower small, with short points, 

 the upper larger, longer (f-ij lines), ending in longer smooth or 

 faintly denticulate hair-points, usually about half the length of 

 the leaf, sometimes longer. Nerve strong, elevated at the back 

 of the leaf, semi-terete ; one or both margins recurved below. 

 Cells at base variable, the marginal usually shorter and wider, 

 more or less hyaline, rectangular, the other basal cells longer, 

 narrowly rectangular or linear, but never very narrow nor 

 elongated ; faintly but not strongly sinuose, nor very incrassate ; 

 all quickly becoming shorter and smaller upwards, sinuosely 

 quadrate, in upper part of leaf very small, incrassate , quadrate 

 or slightly irregular, sinuose, often obscure and opaque. 

 Dioicous. Pericha^tial bracts sheathing; calyptra mitriform or 

 sub-cucullate ; seta cygneous, afterwards erect and flexuose, pale, 

 capsule oval or oblong, not wide-mouthed, pale yellow, when old 

 brown, more or less strongly plicate ; lid shortly rostellate ; 

 peristome teeth red, erecto-patent when dry, 2-3 cleft, papillose. 



Hab. Rocks and walls, not uncommon. Fr. less frequent, summer. 



A variable species, both in habit and structural detail ; rarely without some tinge 

 of yellow, which, with the laxer, wider growth, and the narrower leaves and paler 

 capsules, easily distinguishes it from the last two species. The smooth hair-point 

 separates it from G. decipiens and G. Miihlenbeckii ; G. Stirtoni and G. subsquarrosa 

 differ in the shorter, wider, basal cells ; G. robusta is very near it, but the 

 inflorescence is autoicous, and the cells are usually decidedly more sinuose. Tall 

 robust forms of the present species approach G. elatior ; but the leaves in that are 

 larger, with the basal cells very narrow, sinuose, and incrassate, and the upper larger 

 and more distinct. Except in the twisting of the leaves when dry G. funalis is very 

 like it, but the leaves of that species are almost always shorter, and in proportion to 

 their length broader. 



On the Continent it varies even more than with us, and two or three species have 

 been described from what are, in the opinion of recent authors, only varietal forms. 



