48 APLOPERISTOMI. \_Polytrichwn. 



very distinct. In /3. the stems do not often exceed three or 

 four inches ; the leaves are rather less patent than in a. and of 

 a shorter and broader figure, with their margins whitish and 

 diaphanous; the capsule is ohsoletely quadrangular, and the 

 apophysis indistinct. In both, the leaves are equally decidedly 

 serrated. 



With regard to the P. gracile, Mr. Menzies was inclined at 

 first to consider it only a variety of P. attenuatum, and we 

 must confess that we can ourselves see no difference whatever. 

 Of this latter, which Mohr takes up from Hedwig under the 

 name of formosum, he says, in his German Cryptogamic Flora, 

 "obsoleta et adnata nee distante apophysi a prsecedente (P. 

 communij, statim dignoscenda et bona omnino species," al- 

 though his only character by which it may be distinguished 

 froinformosum, is, that the capsule is obsoletely sexangular, a 

 peculiarity which we cannot find to exist in any of our speci- 

 mens. Wahlenberg, on the other hand, seems to be of opinion, 

 that it is only a slender variety of P. attenuatum ; and he founds 

 the chief distinction of the latter from P. commune in the dia- 

 phanous margins to the leaves. 



7. P. alpinum ; stems elongated branched, leaves patent subulato- 

 lanceolate their margins plane serrated as well as the points 

 of the keels, capsule subovate with an indistinct apophysis. 

 (TAB. XL) 



Polytrichum alpinum. Linn. Sp. PL p. 1593. Menzies in Linn. 

 Trans. Hedw. Sp. Muse. t. 19. Turn. Muse. Hib. p. 85. Smith, Fl. 

 Brit. p. 1377. Engl. Bot. t. 1905. Moug. et Nestl. n. 209. Punch, 

 Deutschl. Moose, t. 57. / 12. Schwaegr. Suppl. v. 1. p. 317. Brid. 

 Meth. p. 198. Hobson, Brit. Mosses, v. 1. n. 17. JDrummond, Muse. 

 Scot. v. 1. n. 16. Hook. FL Scot. P. II. p. 126. Arn. Disp. Muse. p. 

 71. 



P. sylvaticutn. Menzies in Linn. Trans, v. 4. t. 7. f. 6. 



P. arcticum. Swartz, Muse. Suec. t. S.f. 17. 



P. ambiguum. Michaux. 



P. ferrugineum. Brid. Suppl. 



HAB. In subalpine regions, in England, Scotland, and 



Ireland. 



The narrow leaves will distinguish this species from P. urni- 

 gerum, as the branched and somewhat fastigiate stems will from 



