282 MEESIACEiC. 



Var. 8. laxifclium Kindb. Leaves distant, spirally flexuose 

 and divergent, not appressed when dry. 



Hab. Bogs, common. The var. y not common ; the var. $ in drier situations ; 

 the var. 5 Flitwick Marsh, Bedfordshire (Dixon, 1887). Fr. early summer. 



A very variable moss, but not likely to be confused with many others ; in its 

 robust forms it has a great superficial resemblance to Dicranum Bergeri, but the 

 areolation and the highly papillose leaves readily distinguish it from that plant ; some 

 forms too bear a likeness to Milium hornum, which does not, however, inhabit the 

 same localities, nor has it the shining nerve of the present species, and it is of course 

 also readily known by its spinose leaves. Aulacomnium tmgidum is on the whole the 

 species most resembling it, and the var. imbricatum of the present plant sometimes 

 approaches it so nearly that even under the microscope it is difficult to separate them ; 

 as a rule however that variety has the leaves more or less distinctly papillose, and 

 they are rarely so wide, rounded and flaccid as is usual in A. turgidum. 



Perhaps the most striking evidence of the great variability of A. palustre is to be 

 found in the fact that while in their normal state no two mosses could well be more 

 unlike than this species and A. androgynum, it sometimes occurs that dwarfed, slender 

 forms of the first so nearly resemble taller plants of the last as to be with difficulty 

 distinguished ; I have specimens of A. palustre that are indeed in almost every respect 

 similar to other fruiting specimens of A. androgymim. 



The gemmiferous form of this species, usually known as var. polycephalum Hiibn. 

 (G. palustris var. ramosa Lindb., Braithw. Br. M. Fl.), emitting numerous 

 pseudopodia from the axils of the leaves, is rather, I think, a state than a true variety. 

 It is questionable indeed whether even the varieties given above are really more than 

 forms arising from the direct action of certain conditions of the environments. 

 Certainly I have specimens the young branches of which would have to be referred to 

 the var. imbricatum, while the older leaves on the stems are quite of the typical form. 



3. Aulacomnium androgynum Schwgr. (Mnium androgy- 

 num L. ; Orthopyxis androgyna P. Beauv., Braithw. Br. M. Fl.) 

 (Tab. XXXIX. F.). 



Stems slender, rarely i£ inches high, slightly tomentose 

 below, dull green ; usually producing slender leafless pseudopodia, 

 ending in a round head of densely crowded stalked fusiform 

 gemmae. Leaves small, rarely 1 line long, narrowly ovate- 

 lanceolate or linear-lanceolate, when dry loosely appressed and 

 slightly twisted, margin reflexed below, distinctly denticulate at 

 apex; cells uniform or the lower a little elongated, above 

 rounded-quadrate or sub-hexagonal, incrassate ; papillose, 

 perichaetial bracts longer, narrower. Seta }i inch long ; capsule 

 erect, finally oblique or horizontal, almost straight and 

 symmetrical , brown. Dioicous ; male flower terminal, gemmi- 

 form. 



Hab. Banks and rotten tree trunks, frequent. Fruiting very rarely, in summer. 



Usually at once recognisable by the numerous pseudopodia with minute balls of 

 gemmpe ; bearing some resemblance in this respect to Tetraphis pellucida, but at once 

 known by the absence of the cup-shaped bracts, and also by the narrower leaves. 

 Occasionally, as in the case of the specimens mentioned under the last species, it 

 becomes taller, more radiculose, more robust, with longer leaves approaching those of 

 A. palustre in form and even in areolation. 



