208 A MANUAL OF MOSSES 



pletely united into a lattice-work at the apex but free and 

 merely appendiculate below ; spores mature in summer. 



On stones in streams from Nova Scotia to Alabama and 

 west to the Rocky Mountains. Rare in our region. 



Huntingdon : T. C. Porter. (Porter's Catalogue). 



McKean : Bradford. D. A. B. (Porter's Catalogue). 



2. DICHELYMA Myrin. 



Dioicous ; antheridial shoots small, gemmiform ; arche- 

 gonial shoots long; slender to robust, shining, green to 

 golden-brown, blackish below ; branching various, the branches 

 recurved at the apex ; leaves 3-seriate, falcate-secund to cir- 

 cinate, lance-subulate from a slightly decurrent base, carinate- 

 plicate, weakly serrate; costa complete to long-excurrent ; 

 median leaf-cells linear, narrow, the alar not wider; inner 

 perichastial leaves long, tubular, sinistrorsely wound around 

 the seta : seta long ; capsule ovate, soft, brownish ; peristome- 

 teeth 16, lance-linear, obtuse, papillose, spreading either when 

 damp or when dry, often more or less cleft or divided along 

 the median line, trabeculse low and distant; inner peristome 

 longer and sometimes falling away with the operculum, seg- 

 ments filiform, more or less united; lid about as long as urn, 

 conic, mostly oblique and curved ; calyptra enclosing the whole 

 capsule, split along one side, sinistrorse ; spores small and 

 uniform in size. 



A rather widely distributed genus of 7 species; 5 species 

 occurring in North America; 2 species in our region. 



Key to. the Species. 



a. Leaves subulate; costa long-excurrent. 1. D. capillaceum. 

 a. Leaves acute; costa complete or almost so. 



2. D. pallescens. 

 1. Dichdyma capillaceum [Dillenius] Bryologia Europaea. 

 (D. pallescens Sullivant and Lesquereux; Fontinalis capillacea 



Hedwig) . 



Yellowish above, brownish to blackish below; stems 

 slender, often 10-15 cm. long, with a few distichous, divaricate, 

 or one-sided branches; leaves erect-spreading, second to 

 falcate-secund, long-linear from a lance-oval base, about 5-7 

 mm. long, serrulate towards the apex ; costa long-excurrent ; 

 perichaetial leaves linear, thin, ecostate, pale and twisted and 

 reaching above capsule; leaf-cells narrow, linear-rhomboid: 

 seta short, slender ; capsule small, pale yellowish, thin-walled, 

 ovate, the urn truncate and about 1.5-2:1; lid high-conic; 

 peristome double, the teeth shorter than the inner peristome, 

 narrowly linear, densely papillose, segments longer than teeth, 

 constricted at the articulations, pale yellow, papillose, forming 

 3 connected lattice-work only above ; spores mature in late 

 summer. 



