366 MUSCI. Didymodon. 



hyaline at base. Calyptra long, cucullate. Capsule erect, long-pedicelled, long- 

 cylindric, with rostrate operculuni and distinct annulus. Peristome of 16 rather 

 long flat linear-lanceolate fugacious teeth, subentire or more or less divided. 



A genus variously understood and often included in Leptotrichum and Trickostmnum. Schimper 

 refers to it about a dozen European species. It differs from Trichostomum in its softer and more 

 papillose leaves and in the flattened teeth of the peristome without basal membrane. 



1. D. rubellus, Bruch & Schimp. Stems slender, ^ to 1 inch high, in loose 

 mats reddish-ferruginous below : leaves divaricately spreading, crisped when dry, 

 lanceolate and linear, concave and carinate, with revolute margins and papillose 

 both sides, the costa ceasing at the apex : male flowers naked in the axils of the 

 very thin sheathing perichsetial leaves : capsule long-cylindric to oblong or oval, 

 green becoming brownish ; annulus very fragile : teeth pale or reddish. Bryol. 

 Eur. t. 185; Wilson, Bryol. Brit. t. 14 ; Sulliv. in Gray's Man. 2 ed. t. 2 ; Sulliv. 

 & Lesq. Muse. Am.-Bor. Exsicc. n. 106 (2 ed. n. 157). 



Near Soda Springs, Tuolumne Canon (Bolander) ; in the mountains of Nevada and in the Uin- 

 tas ( Watson) ; in the Atlantic States, Europe and Africa. Very variable. 



2. D. cylindricus, Bruch & Schimp. Stems \ to 1 inch high, forming loose 

 flat mats deep or yellowish green above, whitish below : leaves linear-lanceolate, 

 flexuose-spreading, crisped when dry, the flat margins subundulate and minutely 

 crenulate, costa slightly excurrent : capsule narrowly cylindrical, pale brown on a 

 yellowish pedicel, with subulate-beaked operculuni, narrow persistent annulus, and 

 very fugacious peristome. Bryol. Eur. t. 187; Wilson, Bryol. Brit. t. 33; Sulliv. 

 & Lesq. 1. c., n. 106 b (2 ed. n. 158). 



West Humboldt Mountains, Nevada ( Watson) ; in the Eastern States, Europe and India. 



12. LEPTOTRICHUM, Hampe. 



Slender cespitose perennials, terrestrial or on rocks. Leaves several-ranked, lance- 

 subulate, smooth and shining, not crisped when dry, the distinct areolation minute 

 and narrowly rectangular above, looser, more hexagonal and hyaline at base ; costa 

 mostly excurrent. Flowers monoecious or dirccious, terminal and bud-like or the 

 male axillary. Calyptra cucullate. Capsule erect on a long straight pedicel, ovate to 

 cylindrical ; operculum rostrate. Peristome of 16 rather long teeth cleft to the base, 

 or the filiform papillose slightly hygroscopic divisions more or less connate. 



Closely allied to the following genus, with which it is often united. Eight species are Euro- 

 pean, five of them also North American ; ten others are South American. 



1. L. Schimpeii, Lesq. Stems low, 3 or 4 lines high, subsimple, yellowish 

 green : leaves spreading, flexuous or falcate-secund, long and narrowly subulate from 

 an ovate base, subdenticulate at the apex ; costa slender, excurrent : inflorescence 

 monoecious, the male flowers axillary, with large short and obtuse perigonial leaves ; 

 perichaetial leaves broadly clasping, long-attenuate : capsule brown, ovate-cylindrical, 

 upon a yellowish pedicel scarcely over an inch long ; operculuni long-conic, dark 

 red : teeth pale yellow, filiform and smooth, upon an orange or reddish basilar mem- 

 brane thrice broader than the annulus : spores very large. Mem. Calif. Acad. i. 9 ; 

 Sulliv. Icon. Muse. Suppl. 37, t. 24. 



In the Coast Ranges, Mendocino County, Bolander. Resembling L. pallidum, Hampe, of the 

 Atlantic States and Europe. 



L. FLEXICAULE, Hampe, of Europe, was collected by Lynll in the Cascade Mountains of 

 Washington Territory. It is taller (1 to 3 inches), much branched and more densely cespitose, 

 with long-subulate leaves from a lanceolate base : inflorescence dioecious : capsule small, upon a 

 very slender reddish pedicel ; teeth unequal, slender and fragile : spores very minute. Tricho- 

 slomum jlcxicaulc, Bruch & Schimp. Bryol. Eur. t. 180 ; Wilson, Bryol. Brit. 116, t. 42. Ci/no- 

 dontium flcxicaulc, Schwaegr. Suppl. i. 113, t. 29. 



