158 GRIMMIACEiE. 



base, tapering to an acute but not slender nor hyaline point, 

 margin revolute in the lower half, above plane, incrassate, 

 coarsely and remotely toothed in the upper half ; nerve strong, 

 channelled in front, rather indistinct towards apex ; cells at base 

 very narrow and long, regularly seriate, with thick lateral and 

 thin transverse walls, towards the margins wider, shorter ; 

 reddish brown at base ; above, the cells gradually shorten, the 

 walls becoming uniformly incrassate, in all upper part of leaf 

 rounded-quadrate or transversely oval, very regularly arranged in 

 rows, brown and opaque. Seta erect, straight, about half-an-inch 

 long, but variable, several often arising from the same 

 perichaetium ; capsule narrowly elliptic or sub-cylindric, pale 

 brown, thin-walled, smooth ; lid longly and finely subulate ; 

 calyptra narrowly campanulate , lobed at base, plicate, slightly 

 scabrous at apex. Peristome teeth cleft to base, red, paler when 

 old, erecto-patent , segments long, filiform. Spores small. 

 Autoicous. 



Hab. Siliceous rocks and walls in mountainous districts. Common. Fr. early 

 summer. 



A very distinct and easily known plant, the neat cushions with the capsules usually 

 very abundant being conspicuous on nearly every wall in many mountain regions ; the 

 stems are thick and tumid with the large, densely crowded leaves. The serratures of 

 the leaves are sometimes very faint. The basal areolation is peculiar, the regular rows 

 of linear cells with very thin transverse walls, but strongly incrassate longitudinal ones, 

 giving frequently somewhat the appearance of each row being a single cell with 

 transverse partitions rather than a series of separate cells. 



33. GLYPHOMfTRIUM Brid. 



Closely allied to Ptychomitriuiri, but of much smaller habit ; 

 peristome teeth united in pairs, broad, entire. 



The difference in peristome seems sufficient to warrant the 

 separation of these two genera, which in other respects too would 

 seem the more natural treatment. 



1. Grlyphomitrium Daviesii Brid. (Bryum Daviesii Dicks.) 

 (Tab. XXIV. G.). 



In small dense smooth cushions, about half an inch high, deep 

 green. Leaves small (1 line), narrowly linear-lanceolate, tapering 

 to a rather broadly acute point, margin plane or narrowly recurved 

 below, incrassate above, entire, crisped when dry ; nerve strong, 

 thick, vanishing at apex ; cells at base hyaline, thin-walled, 

 hexagonal -rectangular, rather shorter at margin, above elliptic, 

 incrassate, in all the upper half rounded-quadrate, regularly 



