Pottia. MUSCI. 361 



A genus of about 40 species, 13 European. Nearly allied to the Barbula group, with which it 

 is sometimes united. 



* Peristome none or rudimentary. 



H Leaves lamellate on the upper side of the costa, which terminates in a long 



seta. 



1. P. cavifolia, Ehrh. Leaves erect-spreading and subimbricate, obovate-oblong, 

 strongly concave, bearing 3 or 4 membranous lamella? on the costa : capsule emer- 

 gent or exserted upon a short pedicel (1 to 6 lines long), ovate to oblong ; operculum 

 rather long-beaked ; annulus none. Bruch & Schimp. Bryol. Eur. t. 118; Wilson, 

 Bryol. Brit. t. 7. Gymnostomum ovatum, Hedvv. Muse. Frond, i. 16, t. 6. 



In ditches near Carson City ( Watson); Fort Colville, Washington Territory (Lyall); through- 

 out Europe and in the Andes. Very variable. 



2. P. subsessilis, Bruch & Schimp. Eesembling the last : leaves obovate or 

 obovate-oblong, the costa bearing 2 to 4 thickened or membranaceous lamellse and 

 ending in a long white seta : calyptra oblique, campanulate, lobed at base : capsule 

 immersed upon a short straight pedicel, subglobose with a large flattened-convex 

 rostellate operculum and very broad mouth. Bryol. Eur. t. 117; Sulliv. & Lesq. 

 Muse. Am.-Bor. Exsicc. n. 92 (2 ed. n. 118). Schistidium subsessile, Bridel. Pha- 

 romitrium subsessile, Schimp. Syn. Muse. Eur. 2 ed. 150. 



At Los Angeles (Biyclow) ; near Carson City, under sage-brush ( Watson) ; from the Rocky 

 Mountains of British America to Illinois and Texas. Also in South America and in Germany. 

 Separated generically by Schimper upon the character of the calyptra. 



*- *- Costa naked, slightly or not at all excurrent. 



3. P. minutula, Bruch & Schimp. Stems seldom a line long : leaves spread- 

 ing, becoming reddish, ovate- or oblong-lanceolate, with recurved margins and the 

 red costa slightly excurrent : antheridia naked in the axils of the perichaetium or 

 included within one or two perigonial leaves : capsule minute, on a reddish pedicel 

 a line or two long, truncate-ovate, with a large obtusely conical operculum. Bryol. 

 Eur. t. 119; Wilson, 1. c. ; Sulliv. & Lesq. 1. c., n. 91 (2 ed. n. 117). Gymnosto- 

 mum minutulum, Schwaegr. Suppl. i. 25, t. 9. 



At Los Angeles (Bigelow); through Europe and in Northern Africa. 



4. P. truncata, Bruch & Schimp. Stems | to 6 lines high : leaves spreading, 

 obovate-oblong or subspatulate, shortly acuminate and usually mucronate with the 

 excurrent costa, concave at base and carinate above, the margins flat : capsule trun- 

 cate-obovate, with an obliquely beaked flat-convex operculum deciduous with the 

 upper portion of the columella. Bryol. Eur. t. 120 ; Wilson, 1. c. ; Sulliv. in Gray's 

 Man. 2 ed. 629, t. 2; Sulliv. & Lesq. 1. c., n. 90 (2 ed. n. 116). G 'ymnostomiim 

 truncatum, Hedw. Muse. Frond, i. 13, t. 5. 



Var. subcylindrica, Bruch & Schimp. Leaves ovate-lanceolate, the costa more 

 excurrent : capsule subcylindrical. 



Wet meadows near Carson City ( Watson), the variety. New England to Pennsylvania, and 

 very common throughout Central Europe. 



5. P. Heimii, Bruch & Schimp. Somewhat taller and stouter: leaves flexuose- 

 spreading, the lower remote and broadly lanceolate, the upper crowded, oblong- 

 lanceolate, acute or acuminate, serrate at the apex, with flat margins and the reddish 

 costa ceasing at or below the apex : inflorescence polygamous : capsule reddish 

 brown, on a pedicel | to 1 inch long or less, truncate-obovate or oblong ; operculum 

 flat-convex, obliquely long-beaked, remaining attached to the columella. Bryol. 

 Eur. t. 124 ; Wilson, 1. c. ; Berkeley, Brit. Moss. t. 23, fig. 3 ; Sulliv. & Lesq. 1. c., 

 n. 115. Gymnostomum Heimii, Hedw. 1. c., i. 80, t. 30. 



In ditches near Soda Springs on the Upper Tuolumne (Bolander); in the West Humboldt 

 Mountains, Nevada, and in the Wahsatch ( Watson); and in the Kooky Mountains from British 

 America to Colorado. Also in the Andes to Cape Horn, and in Europe. 



