386 leskeace^:. 



6. Thuidium recognitum Lindb. (Hypnum recognition 



Hedw. ; T. delicatulum B. & S., non Mitt, nee Lindb.) 



(Tab. LI. D.). 



Resembles slender forms of T. tamariscinum but is usually 

 of a yellowish, not bright green, the branching bipinnate, not 

 tripinnate (a single secondary branch here and there alone, in 

 luxuriant specimens, producing one or two tertiary branchlets) ; 

 stems more linear in outline, not distinctly deltoid nor lanceolate, 

 owing to the primary branches being sub-equal ; less frequently 

 interrupted than in that species. Branch-leaves and apical cells 

 as in T. delicatulum. Perichaetial bracts not ciliate, denticulate 

 only. Capsule arcuate, large, rather slender. 



Hab. Mountain rocks, and among grass in meadows etc., principally in 

 calcareous districts. Frequent, probably overlooked for T. tamariscinum. Fr. very 

 rare, winter. 



Distinguished from T. tamariscinum by the apical cells of the branch-leaves, and 

 from both that and the last by the branching being bipinnate only and by the non- 

 ciliate perichsetial bracts. I can find no difference between the upper cells of the 

 branch-leaves in this and T. delicatulum, such as Husnot describes. 



Philibert (Rev. Bry. 1893, pp. 33 sqq. ) describes a new species, T. intermedium, 

 closely allied to the present, but differing in certain characters which if constant might 

 be held of importance. I find however some characters which he attributes to T. 

 intermedium undoubtedly existing in the same specimens with others which he 

 considers characteristic of T. recognitum ; while the characters derived from the stem- 

 leaves, such as the revolution of the margins and length of nerve, are extremely 

 variable even on the same stem ; and I have never found the nerve excurrent as he 

 describes it in T. recognitum, nor even percurrent. I doubt very much, therefore, 

 the specific value of T. intermedium. 



Order XXV HYPNACEjE. 



Stems variously branched ; leaves variable in form and in 

 direction. Cells narrow and elongated, from shortly rhomboid to 

 narrowly linear-vermicular, at least twice as long as wide and 

 usually much longer ; smooth or very rarely sparsely and 

 minutely papillose ; nerve single, double, or none. Capsule on an 

 elongated seta, usually arcuate, less commonly erect and 

 symmetrical ; peristome well developed ; inner almost always 

 with a distinct and more or less elevated basal membrane, 

 frequently with cilia between the processes. 



Under this Order I have included all the British genera of 

 pleurocarpous mosses with elongated, smooth areolation and well 

 developed Bryoid peristome ; those species of course excepted 

 which with the above characters are separated, on important 

 grounds, under Neckeraceae and Hookeriaceae. The cells, though 



