NEW BRITISH MOSSES. 191 
It is also given under that name by Moug. and Nestler as 
No. 802 of their Stirp. Crypt. Vogeso-Rhen., 1826.” 
19. Tortula ambigua, B. et S., “dioica; brevicaulis; foliis 
patulis, ligulato-lanceolatis, obtusis, apice subincurvis, cap- 
sula cylindrica erecta, annulo simplici subpersistente in- 
structa; operculo breviori, elongato-conico, margine in- 
tegro; calyptra brevi, solum operculum obtegente; peris- 
tomio brevi, semel contorto.” Bryol. Eur. 
“ Barbula rigida, trunco exiguo, foliis patentibus margine 
involutis, thecis oblongis erectis. Hedwig. Musc. Frond. I, 
p. 65, T. 25, fig. 3 et 5; ejusd. spec. musc. p. 116. Bridel 
Bryol. univ. Y, p. 528, et Suppl. I, p. 824;” (fide B. et 8.) 
Has. On a mud capped wall by the side of the road leading 
out of New Malton towards York, where I found a single 
patch growing along with abundance of T. rigida, Nov. 19. 
1844, 
This new species belongs to the small group of Aloid 
Tortule, which comprehends besides it only three species, 
viz. Tortule rigida Schultz (T. enervis Musc. Brit.) T. aloides 
B. et S. (T. rigida Turn., Musc. Brit.) and T. brevirostris Hook. 
et Grev. Between the two former of these it is almost inter- 
mediate, but differs from both in the more spreading leaves, 
with usually cucullate apices. From T. rigida, it differs far- 
ther in the longer leaves, the longer and cylindrical (not 
ovato-oblong) capsule, the shorter operculum, the much nar- 
rower annulus, the peristome only once twisted (in T. rigida 
3 or 4 times), and ¢he calyptra merely covering the lid, but in 
T. rigida sheathing half the capsule. From T. aloides it may 
be distinguished by the broader and less acute leaves, with a 
much broader and thinner nerve, the capsule erect and of a uni- 
form colour, while that of T. aloides is curved and of a deeper 
hue on the upper than the underside, the subulate (not ros- 
trate) lid, the broader basal membrane of the peristome and the 
smaller seeds, 
I have attentively studied Tortula ambigua and believe it a 
good species; for although I have now and then found a cap- 
sule of T, rigida with the peristome equally short and only 
