TRTCHOSTOMUM. 



59 



of the characters of both, that it seemed impossible to deter- 

 mine to which they should be referred. Our var. y. has 

 leaves still longer than those of rufescens, but not serrated, 

 nor so strongly reticulated ; with the capsules as in . We 

 cannot find the D. rigidulum and D. callistomum to differ 

 in any way from our common D. varium, 



D. heteromaWim; stems branched; leaves subulate, falcato- 

 secund, nearly entire ; capsule ovate, subcernuous ; lid with 

 a long beak. (T A B. XVIII.) 



D. heteromaljum. Hedw. St. Cr.v, 1. t.26. Turn. Musc.Hib.p. 61. 

 Engl. Bot. t.- 1272. Mvug. et Nestl. n. 121. D. orthocarpum. Hedw. 

 Sp. Muse. t. 30. (according to Mohr.) D. curvatum. Hedw. Sp. Muse, 

 t. 31. D. interruptum. Hedw. Sp. Muse. t. 29. Dill. Muse. t. 47. 

 /. 37 & 38. 



HAB. On moist banks. 



We have noticed above that this species can scarcely be 

 distinguished from D.falcatum and Z). Starkii, but by the 

 want of the struma at the base of the capsule, Has an al- 

 pine situation any effect in producing such a variation ? 



D. subulatum; stems branched; leaves from abroad sheath- 

 ing base subulate-setaceous, secund, entire ; capsule ovate^ 

 subcernuous ; lid with a long beak. (TAB. XVIII.) 



D. subulatum. Hedw. Sp. Muse. t. 34. Turn. Muse. Hib. p. 63. 

 ngl. Bot. t. 1273. 



HAB. Moist banks. 



Perhaps Mohr was right in uniting this species with the 

 preceding one ; for we must confess that we can perceive 

 no other differences than the slight ones mentioned in our 

 specific characters. 



19. TRICHOSTOMUM. 



GEN. CHAR. Frmtstalhs terminal; Peristome of 16 

 equal teeth divided to the base, or 32 placed toge- 

 ther in pairs ; Calyptra mitriform. (TAB. II.) 



We need only repeat here what we have already said under 

 the genus Grimmia, that it and the present one are very closely 

 Allied both in natural and essential character. Trichostomum is 

 to Didymodon what Grimmia is to Weissiq. 



