ACAULON. 163 



an apiculus, immersed, cleistocarpous. Calyptra very small, 

 conical, irregularly torn at the base. Spores rather large, 

 granulated. Columella perfect. Male flower on a basal branch 

 or basal radicles. 



These little plants are in the areolation somewhat inter- 

 mediate between the genera Ephemerum and Phascum ; in 

 habit, however, they are much nearer the latter, especially P. 

 cuspidatum, and it can hardly be doubted that they are rightly 

 placed here, whatever the position of Ephemerum. From all 

 species of Phascum and indeed from all the cleistocarpous mosses 

 with which they are likely to be confused, the round capsules 

 without distinct apiculus except a very minute one in A. 

 mediterraneum, and the inflated, usually denticulate bracts easily 

 distinguish them. 



/PerichEetial bracts convolute, not keeled ; seta straight 2 



\ Perichstial bracts connivent, keeled ; seta arcuate 2. triquetrum 



( Capsule not or minutely apiculate ; bracts usually denticulate at apex, with 



2-! excurrent nerve /. muticum 



[ Capsule distinctly apiculate ; bracts entire or sub-entire I* mediterraneum 



1. Acaulon muticum CM. (Phascum muticum Schreb. ; 

 Sphserangium muticum Schp., Syn.) (Tab. XXV A.). 



Gregarious, minute plants, oval in outline and slightly 

 cuspidate by the rather elongated upper leaves or bracts, pale 

 greenish white or yellowish. Lower leaves very small, concave, 

 roundish-ovate ; about three upper much larger, the two upper- 

 most or inner perichaetial bracts being the largest, convolute, 

 cymbiform, rounded at back, not keeled, enclosing and covering 

 the capsule ; irregularly denticulate or sinuose at the rounded 

 obtuse apex, nerve distinct, usually excurrent in a short erect 

 mucro, margin plane ; lower cells hyaline, rectangular, thin- 

 walled, rather large, the upper smaller, rhomboid-hexagonal or 

 sub-rectangular, smooth, the marginal ones often forming a more 

 or less distinct border. Capsule on a short straight seta, 

 immersed, spherical, or with a minute obtuse apiculus, orange- 

 brown ; calyptra very small, torn at the base. Male flower on a 

 basal branch or basal radicles. 



Var. ft. minus Braithw. (Phascum muticum var. minus Hook. 

 & Tayl.). Smaller, shorter, bracts hardly exceeding the capsule, 

 more shortly pointed, entire. 



Hab. Bare sandy spots, not unfrequent. The var. 0, Torquay ; Sussex. Fr. 

 winter and early spring. 



