' 



' 



II 



68 DIDYMODON. 



lact-a. Hcdw. St. Cr. v. 2. t. 26. Cynontodium capillaccum.^ Hediv. 

 Sp. Muse. Trichostomum capillaceum. Turn. Muse. Hilt. p. 35. Engl 

 Bot.t. 1152. 



HAB. On banks in mountainous situations. 



This species is most nearly allied to D. inct'nialum, of all 

 the British mosses, in general appearance. The stems never- 

 theless are much longer, and the capsule erect and more 

 blender ; and when the peristomes are subjected to the mi- 

 croscope they almost seem to belong to different genera, so 

 much narrower are the teeth of the present species. The 

 stems vary exceedingly in length, according as the plant is 

 found in wet or dry situations. 



8. D. heteromallum ; stems rather short ; leaves subsecund, su- 

 bulate ; capsule ovato-cylindraceous ; lid conical. (TAB. 

 XX.) 



Weissia heteromalla. Hedtc. St. Cr. v. 1. t. 8. Grimmia hetero- 

 msilla. Enfft. Bot. t. 1899. Tvrn. Muse. Hib. p. 30. Bryum Weissia* 

 Dicks. Didymocion homomallum. Hedw. Sp. Muse. t. 23. f. 1-7- 



HAB. On the earth in mountainous situations. 



We cannot avoid considering the Didym<idon homomal- 

 lum of Hedwig, Wahlenberg, an.d Mohr, as not specifically 

 distinct from our D. heteromallum (Weissia heteromalla of 

 those authors,) although much stress has been laid on the 

 diagnosis by the two latter. Specimens of the former, froin 

 the German botanist Ludvvig, in Mr. Turner's Herbarium, 

 have the greatest similarity with our plant, differing only in 

 their smaller size, darker colour, and more secund leaves ; 

 nor indeed does the figure in Hedwig's Species Muscomm 

 (TAB. XXIII.) differ in any essential particular. Thus 

 much fertile general appearance of the two plants, the fo- 

 liage and capsules. In regard to the peristome, we find both 

 to have sixteen long, filiform, occasionally perforated teeth, 

 placed in rather distant pairs, so that their approximation is 

 not very easily discoverable ; and hence it has happened that 

 in the figures of what is called Weissia heteromalla in Hed- 

 wig's Stirpes, the teeth are represented at equal distances. 

 Wahlenberg appears to have described, under his IVeissia 

 heteromalla , a plant different from ours ; since he says 

 " rarissimus muscus a paucis botanicis visus ;" and again, 

 ff abunde differt a Didymodonte homomallo^ foliis brevibus 

 neutiquam arcuatis, sed tantum leviter versus unum latus 

 spectantibus, basi vaginantibus, atque caule subfiliformi 

 longiore ;" characters which do not well accord either with 

 our specimens or with Hedwig's figures. Our plant is re-i 



