MtJSCI. (MOSSES.J 633 



spreading, entire, usually revolute on the margins, of a minute dot-like areola- 

 tion, except at the marginal base, the areolae there being larger, rectangular, and 

 pellucid. (Name from opdos, straight, and 6pi£, Tpt^os, a hair, in allusion to the 

 straight hairs on the calyptra.) 

 i 1. Capsule immersed or slightly exserted. Monoecious {except in No. 5 and 6). 

 # Peristome single: cilia wanting. 



1. O. cupillattmt, Hoffm. Stems nearly 1' high; leaves lanceolate, 

 keeled ; capsule immersed, with 16 stria; ; teeth of the peristome nearly equidis- 

 tant ; calyptra sparsely hairy ; male flower terminal. — On rocks, Niagara Falls, 

 Drummond: Lake Superior, Agassiz. (Eu.) 



2. O. Stui'mii, Hoppe & Hornsch. Very like the last species ; but its im- 

 mersed and obovate capsule is indistinctly 8-striated ; the male flower axillary. — 

 Texas, Wright. (Eu.) 



3. O. andmaluill, Hedw. Separated from the preceding (to which it 

 approaches closely) mainly by its exserted and distinctly 8-striated capsule. — 

 Rocks, near Salem, Mass., Lesquereux: Lake Superior, Agassiz. (Eu.) 



4. O. Tex»nuin, Sulliv. Larger than No. 2, which it resembles, but 

 its immersed capsule is oblong-pyriform and distinctly 8-striated ; teeth of the 

 peristome in pairs ; calyptra very hairy ; leaves longer, narrower, and more re- 

 curved-spreading. — Texas, Wright : Santa Fe, New Mexico, Fendkr. 



* * Peristome double. 



5. O. obtlisifdlium, Schrad. Stems 6" -10" high; leaves when moist 

 erect-patent, not recurved, ligulate from an oblong base, obtuse, concave, some- 

 what convolute on the margins, strongly papillose, the costa vanishing much 

 below the point ; capsule immersed, oblong-pyriform, the long apophysis gradu 

 ally tapering into the very short pedicel ; cilia of the peristome 8, composed of 

 two rows of cellules half as wide as the teeth ; calyptra glabrous. — Trees, Cam- 

 bridge, Massachusetts, Lesquereux. (Eu.) 



G. O. exiguum, Sulliv. Nearly related to No. 5, but much smaller ; 

 stems 3'' - 5" high ; leaves more acute, scarcely papillose : costa stouter, extend- 

 ing to the point; the areolae at the base not so enlarged; capsule oval; the 

 apophysis rather short ; pedicel longer ; cilia of the peristome 8, carinate, com- 

 posed of two rows of cellules fully as broad as the teeth ; operculum convex, 

 apiculate. — Base of trees, Santee Canal, South Carolina, Ravenel. — The small- 

 est of our Orthotricha. — This and the related species have, scattered on the 

 surface of their leaves, a few articulated excrescences (Conferva Orthotrichi) . 



7. O. Sldsjeri, Brid. Leaves spreading-recurved, when moist narrowly 

 ligulate from a ventricose concave base, canaliculate, plane on the margins 

 above, revolute below, somewhat acute at the apex ; capsule and calyptra as in 

 No. 5 ; cilia 8, simple, filiform. — Trees, Lake Superior, Agassiz. (Eu.) 



8. O. Strang'itlatura, Beauv. Stems short, compact ; leaves broadly 

 ovate-lanceolate, carinate, somewhat obtuse, the margins strongly reflexed ; cap- 

 sule oblong, somewhat pyriform, immersed, very much constricted below the 

 mouth when dry; cilia of the peristome as in the last; calyptra hairy. — On 

 trees ; very common. 



