290 BKYACEJi:, [Pterogonium. 



hairs. Capsule regular or slightly curved. Peristome double ; 

 teeth long, densely articulate ; segments scarcely half as long. 



1. P. gracile, Swartz. Tufts loose, yellowish green ; sec- 

 ondary stems simple at base : capsule cylindrical-oblong, chest- 

 nut-color, with a narrow orifice; peristome pale, fragile; 

 segments short, narrowly linear; annulus compound. — Muse. 

 Suec. 26; Bryol. Eur, t. 467; Sulliv. & Lesq. Muse. Bor.-Amer. 

 ed. 2, n. 349. II>/pnu7n gracile, Linn. Mant. ii. 310. Pterigy- 

 nandnim gracile, Hedw. Muse. Frond, iv. 16, t. 6. Nechera 

 gracilis, Muell. Syn. ii. 97. 



Var. duplicato-serratum, Lesq. Plants more slender, 

 filiform: leaves duplicate-serrate. — Mem. Calif. Acad. i. 30. 

 Leptohymenium duplicato-serratum, Hampe., Linnasa, xxx. 460. 



Hab. On rocks, California (Bolander, Bauer, Watson); common and 

 variable. 



From the numerous specimens examined it is evident that the moss de- 

 scribed by Hampe represents a mere variety. The California specimens, 

 though identical in their essential characters with the European form, 

 differ sometimes in the more marked denticulations of the leaves, and in 

 the annulus, which appears a little longer and is sometimes composed of 

 three cells instead of two. These unimportant differences are merely cas- 

 ual, and not observable upon all the specimens. 



2. P. brachypterum, Mitten. Monoecious: stems pro- 

 cumbent, irregularly pinnately divided into short branches: 

 leaves closely imbricated, broadlj^ deltoid-ovate, narrowly acu- 

 minate, concave ; borders flat in the lower part, minutely 

 serrulate above ; costa vanishing above the middle ; cells of the 

 basal angles small, found, the others oval, longer at the apex, 

 all distinctly papillose ; perichastial leaves erect, ovate-acuminate, 

 very entire, nerved to above the middle : caj^sule cylindrical- 

 oval, erect, equal ; pedicel long, thickish, yellow ; operculum 

 short-conical ; teeth short, yellow, attached under the orifice, 

 connate at base ; cilia none : male flowers gemmiform, large. — 

 Journ. Linn. Soc. viii. 37. 



Hab. British America (Drummond). 



The author remarks that this plant closely corresponds in structure and 

 appearance to the Abyssinian P. abbreviatum, Schimp., and is quite dis- 

 tinct from any other American moss. 



111. ANTITRICHIA, Brid. (PI. 4.) 



Secondary stems of various lengths, sometimes very long, 

 procumbent or pendent, simjjle or much divided, more or less 



