200 TORTULACEiE. 



Hab. Limestone walls and mortar ; frequent. Fr. spring and summer. 



As pointed out above this species is at once recognised by its much less tapering, 

 less acute leaves, from B. Hornschuchiana, and is indeed a plant in no way likely 

 to be confused with any other ; the thick nerve and revolute margin give a solid, 

 opaque appearance to the leaves quite different to that of B. convoluta ; and the 

 colour is usually a deeper green, less yellow than in that species. 



13. Barbula convoluta Hedw. (Tab. XXX. B.). 



Rather 'taller, \-\ inch high, in more swollen cushions, bright 

 yellowish green. Leaves erecto-patent, recurved, crowded, 

 strongly curled when dry ; small, oblong-lanceolate or Ungulate, 

 slightly narrowed but not tapering at apex, slightly acute, or rather 

 obtuse and apiculate ; margin slightly recurved at base on one or 

 both sides, elsewhere plane, crenulate with bifid papillae ; nerve 

 yellowish, pellucid, vanishing in or below apex or very shortly 

 excurrent in a minute apiculus ; areolation sub-quadrate, obscure, 

 small ; at base pellucid or hyaline, elongate-rectangular. 

 Perichaetial bracts long, convolute, sheathing, apiculate, inner 

 nerveless ; seta long, slender, straw-coloured, twisting to the left 

 when dry; capsule small, oblong, reddish brown; annulus 

 distinct ; peristome much twisted. Dioicous. 



Var. fi. Sardoa B. &S. (Trichostomum undatum Schp., Syn. ; 

 Barb, commutata Jur., nonn. auct.). Taller, in dense tufts ; 

 leaves, especially the comal, longer, less recurved ; capsule longer. 



Hab. On the ground and on wall-tops ; frequent. The var. (3 rare. Fr. 

 spring. 



Readily known by its pale yellow slender seta, and the long sheathing perichaetial 

 bracts. Otherwise it much resembles small states of B. utzguiculata, but the margin 

 is very slightly recurved, the nerve usually vanishing and never so stoutly and 

 distinctly excurrent as in that species. The leaves are much more translucent than in 

 the two previous species, and less neatly and regularly curled when dry than in B. 

 revolnta. 



14. Barbula unguiculata Hedw. (Bryum unguiculatum Huds.) 



(Tab. XXX. C). 



A very- variable plant, usually growing in small dense tufts, 

 or larger patches ; yellowish green, \-\ inch high. Leaves 

 erecto-patent and recurved, or sometimes spreading and slightly 

 squarrose, closely imbricated and spirally twisted when dry, with 

 the nerve at back pale and glossy ; Ungulate or oblong-lanceolate, 

 slightly narrowed towards apex, but never acuminate, obtuse, 

 mucronate with the stout yellowish excurrent nerve, which is 

 papillose at back ; margin recurved, plane towards apex ; basal 



