628 MUSCI. (MOSSES.) 



21. DESlttATODON, Brid. (Tab. 16.) 



Calyptra cuculliforra. Operculum conic, obtusely rostrate. Capsule oval- 

 oblong or cylindrical, annulate, long-pedicellate. Peristome single : teeth 16, 

 subulate, 2 - 3-cleft, united by a basilar membrane. Inflorescence monoecious 

 or dioacious. Plants of rather low stature, growing on the ground or on rocks, 

 in general habit, ramification, and structure of leaves having much in common 

 with Trichostomum and Barbula. (Name from 5eo-/ia, -arcs, a band, and o5coi>, 

 a tooth, in allusion to the membrane uniting the teeth.) 



1. D. arennceilS, Sulliv. & Lesqx. (Muse. Bor.-Amer., No. 93.) 

 Stems 2" -3" high, gregarious ; leaves oblong, linguseform, very obtuse, slightly 

 denticulate at the apex ; apiculate by the excurrent costa ; capsule cylindrical, 

 tapering into the pedicel (4" -5" long) ; annulus simple, persistent; teeth of the 

 peristome 2-cleft, straight, white. Sandstone rocks, Ohio. Near D. flavicans. 



2. D. plinthobfllS, Sulliv. & Lesqx. (Muse. Bor.-Amer., No. 94.) 

 Stems 2" - 5" high, fastigiately branched ; leaves erect, elongated-oblong, very 

 obtuse, carinate-concave, narrowly reflexed on the margins ; areolation minute, 

 opaque, dot-like above, larger oblong and pellucid below ; costa excurrent into 

 a smooth white hair-point nearly as long as the leaf; capsule elliptic-cylindrical, 

 its mouth orange-red ; operculum J the length of the capsule ; teeth of the peri- 

 stome pale yellow, more or less cloven along the medial line ; annulus large : 

 dioecious. (Barbula muralis, James; not of Hedw.) Grows in hoary or pale- 

 green and dense patches, on brick pavements, Charleston, _S. Carolina, Ravenel: 

 on the walls of the College at Nashville, Tennessee, Lesguereux. (Tab. 16.) 



22. I>ID\ ITIODON, Br. & Sch. (Tab. 16.) 



Calyptra cuculliforra. Operculum conic, shortly and obtusely rostrate. Cap- 

 sule subcylindrical, annulate, long-pedicellate. Peristome single : teeth 16, 

 linear-lanceolate, entire, or more or less bifid, rather short, fugacious, and with- 

 out a basilar membrane. Inflorescence various. Very nearly allied to the last 

 genus ; and it is questionable if either is entitled to rank higher than as a section 

 of Trichostomum. (Name from didvpos, twin, and oo>i>, a tooth.) (Tab. 16.) 



1. D. rilbellllS, Br. & Sch. Stems '-!' high, loosely caespitose; leaves 

 spreading, oblong-lanceolate, recurved on the margins, costate to the apex, the 

 upper ones dull-green, the lower reddish ; annulus simple ; antheridia naked in 

 the axils of the pericha3tial leaves. Pennsylvania, on the ground ; rare 

 (Tab. 16.) (Eu.) 



2. D. lliridllS, Hornsch. Rather smaller than the last; leaves lurid- 

 green, rigid, ovate-lanceolate, with a reddish-brown costa, ceasing at the apex ; 

 peristome minute, irregular; male flower terminal on a separate plant. Falls 

 of Niagara, Drummond. (Eu.) 



TRIBE VIII. DISTICHIE.E. 



23. DISTICHIUM, Br. & Sch. (Tab 16.) 

 Calyptra cuculliform, long-rostrate. Operculum conic, short. Capsule oval- 



