BRYUM. 329 



* Bryum pseudo-triquetrum Schwgr. (Mnium pseudo- 



triquetrum Hedw. ; B. ventricosum Dicks., Braithw. Br. M. Fl.) 



(Tab. XLIV. D.). 



Differs from B. bimum essentially in the dioicous inflorescence, 

 the male flower being large, terminal, sub-discoid ; the perigonial 

 bracts widely cordate or ovate-cordate. It is usually also, but 

 not constantly, a stouter, more rigid plant, with the leaves more 

 rigid and less shrinking when dry, of a darker colour ; the capsule 

 rather wider and more ventricose, more often curved and frequently 

 gibbous on the under side, but none of these characters are 

 constant. 



Var. /3. compactum B. & S. Shorter and more compact ; 

 leaves more crowded ; seta shorter ; capsule shorter and wider. 



Hab. Bogs and wet places ; frequent in mountainous districts ; the var. $ rare. 

 Fr. summer. 



After much hesitation I have thought it right to unite this plant with B. bimum, 

 being convinced that, beyond the inflorescence, there is no real difference between the 

 plants. The pale, lax-leaved, more flaccid plants certainly as a rule belong to B. 

 bimum, but this is not invariably the case ; and on the other hand B. bimum is 

 undoubtedly often fully as rigid and compact, and with the leaves of exactly the same 

 form, while the same variations of capsule are found in the one as in the other. I 

 have found the two plants growing together luxuriantly and betraying no marked 

 differences of any kind except in the inflorescence. The leaves are usually concave, 

 in some forms very markedly so. 



16. Bryum neodamense Itzigs. (Tab. XLIV. E.). 



Tall, slender, brownish green, slightly branched; leaves very 

 distant except at the summit of the stem, where they form a close 

 coma, slightly and narrowly decurrent, broadly oval from a narrow 

 base, very concave, obtuse except occasionally in the comal leaves ; 

 entire, margin erect, plane, or very slightly recurved below ; 

 nerve vanishing below the summit, rarely in the comal leaves 

 reaching apex or very shortly excurrent ; cells a little wider than 

 in the last sub-species, the marginal forming a distinct border. 

 Capsule rather shorter than in that, obovate-pyriform, neck 

 shorter than the capsule itself, lid shortly apiculate. Dioicous; 

 male flower as in B. pseudo-triquetrum. 



Hab. Sandy heaths by the sea ; Southport ; Sands of Barrie. Fruit very rare, 

 summer. 



This species is quite distinct in its tall stems with lax, very rounded, concave, 

 almost cochleariform, obtuse leaves, which however in the comal tuft show some 

 approach to the more usual Bryoid outline. In the almost plane margin of the leaves, 

 as well as in their form it appears to be very distinct from B. fiseudo-triquetrum. The 

 fruit has only once been found in Britain. 



