64 DIDYMOtJOti. 



ascendant, from one to two or three inches in length, simple? 

 or branched ; often swelling towards the centre, and sharper 

 towards the point, sometimes cylindrical ; leaves concave^ 

 nerveless, but striated, the margins entire ; those of the pe- 

 richaetium long, cylindrical, sheathing, especially the inte- 

 rior ones, which are half as long as the fruitstalk, and closely 

 enveloping it. Fruitstalks lateral, about an inch long ; lid 

 rostrate. 



We have been obliged to frame such a character as would 

 exclude the L. canarietise of Schwaegrichen, of which he 

 says the leaves are lanceolate-acuminate, loosely imbricated^ 

 and that the capsule is globose. With regard to the L. Mo- 

 rensis of the same author (Uypnum Morense Schleicher)^ 

 we have abundant specimens, which we have received from 

 Schleicher himself, and others that we have gathered in 

 Switzerland, and can safely assert that they differ in nothing 

 from the common appearance of our plant, except in having 

 the branches somewhat shorter and more tumid. The 

 fe folia octo-faria oblique imbricata" may often be seen as 

 distinctly upon our specimens of L. sciuroides as upon 

 L, Morensis. 



The fructification is very scarce in this country ; fine 

 specimens of it have been gathered by Mr. Lyell in the New 

 Forest* 



21. DIDYMODON. 



GEN. CHAR. Fruitstalks terminal; Peris tome single 1 , 

 of 16 or 32 teeth approaching in pairs, or united 

 at the base; Calyptra dimidiate. (TAB. II.) 



In natural habit the plants of this genus approach on the one 

 hand to the Weissice, and on the other to the Dicrana. With 

 the former, two species are liable to be confounded, viz. Didy- 

 modon inclinatum and D. keteromallum^ each of which has but 

 sixteen teeth, and their approximation in pairs is with difficulty 

 discoverable. In D. nervosum and purpureum, besides being 

 united in pairs at the base, we find them connected in various? 

 parts of their length by transverse bars ; and in D. nervosum 

 their direction appears not erect but oblique. In D. trifariiim 



