TRICHOSTOMEI. 253 



It generally affects a calcareous soil. 



b. Nerve of leaves round ; teeth much twisted, springing from a 



membrane much shorter in general than themselves (Barbula). 



* Leaves widely lanceolate or more or less spathulate. 



8. T. canescens, Bruch ; leaves more or less'obovate, hair- 

 pointed; margin reflexed; sporangium elliptic, equal, thin- 

 walled; lid conical, blunt; ring rather broad; basal mem- 

 brane tubular, rather long. Hook, fy Wils. t. xliii. 



On trees, soil, etc., principally in argillaceous districts. 

 Sussex, Mr. Jenner. Bearing fruit in spring. 



Distinguished from T. muralis by the shorter, wider, softer 

 leaves, their less recurved margin and the elongated basal tube, 

 which is one-third or half as long as the teeth, presenting in 

 fact the characters of Syntrichia. 



9. T. marginata, Wils. ; monoicous ; leaves oblongo-lan- 

 ceolate, with a thickened yellowish margin; nerve slightly ex- 

 current ; sporangium oblong ; lid shortly rostrate, basal mem- 

 brane narrow. Hook, fy Wils. t. xliii. 



On walls and on the ground. North and south of England. 

 Rare. Bearing fruit in early summer. 



Leaves narrower than in T. muralis, which it much re- 

 sembles ; margin distinct, of a double row of cells, not at all 

 reflexed ; ring broader. The British specimens in general have 

 narrower leaves. Schimper's character, " broadly oblongo- 

 lanceolate," will not apply to them. 



10. T. muralis, Hedw. ; monoicous ; stem short ; leaves 

 oblong, subspathulate ; margin strongly recurved ; sporangium 

 oblong, erect ; lid shortly rostrate, basal membrane narrow ; 

 ring narrow ; subpersistent. Hook, fy Wils. t. xii. ; Eng. 

 Bot. /. 2033. ; (Plate 22, fig. 3) ; Moug. % Nest. n. 127, 

 1112. 



