Jennings: Manual of Mosses — 4. Fissidentaceae 73 



coming rectangular, the sheath being bordered, especially in its upper part, by 

 a border one to four cells wide, of elongate and more or less prosenchymatous 

 cells, all cells moderately incrassate or more so in border of sheath: capsule on 

 an erect, somewhat flexucus, stout, reddish pedicel 2-5 mm long; capsule 

 oblong-oval, narrowed to pedicel at base, somewhat constricted below mouth, 

 smooth, reddish-yellow, about 0.5-0.7 mm long; operculum conic-rosrrate, 

 about two-thirds the length of the capsule; calyptra narrow, dimidiate; teeth 

 red, split to the middle into two awl-like prongs which have spiral thickenings, 

 closely infolded in wet specimens, inserted a little below edge of mouth; 

 spores sm.ooth, about .020 mm in diameter. Mature in September. 



On stones and rocks in stream beds, especially in ravines. Southern Can- 

 ada, United States east of the Rockies, south to North Carolina, England. 



Allegheny Co.: On sandstone rocks, ravine of Powers Run, November 30. 1909. 

 O.E.J. Fayette Co.: Cheat Haven, September 3-6. 1910. O.E.J, and G.K.J, (figured). 



6. FiSSIDENS CRISTATUS Wilson 



(f. decipiens De Notaris) 



Plate XV 



Usually tufted, branching from the base, green to dark green; stem erect, 

 1-2 cm high; leaves numerous, ascending, imbricate, the upper reaching 2.5 mm 

 long, oblong-lingulate, acute, crenulate below, irregularly serrate above, inferior 

 lamina narrowed and somewhat decurrent at base, sheath e.xtending half-way 

 to apex or a little above; costa strong, ending just below or in the apex, some- 

 times a little excurrent; leaf-cells irregularly angular to rounded-he.xagonal, 

 about .003-. 012 mm. in diameter, some of these ne.xt to the costa larger, the 

 marginal 3 or 4 rows paler and forming a rather obscure belt around the leaf, 

 all cells incrassate: seta ascending, usually about 1 cm high, smooth, light chest- 

 nut color, arising from the lower half of the stem; capsule oblong, smooth, 

 about 2 mm long, tapering to the seta, ascending to nearly erect, chestnut- 

 brown, constricted below the mouth at least when old; peristome bright red- 

 chestnut, the teeth split at one-third above the base into two very slender, 

 trabeculate, somewhat spirally papillose prongs; operculum conic, rostrate; 

 spores about .020 mm, in diameter, smooth, pale yellowish, globose. Mature 

 in winter or early spring. 



On moist soil and stones or occasionally at base of trees. Nova Scotia to 

 the Gulf States and the Rocky Mountains, Europe, Asia. 



Known from the following counties: Allegheny, Armstrong, Cameron, Crawford, But- 

 ler, Elk, Fayette, La.vrence, McKean, Somerset, Warren, Washington, and Westmoreland. 

 Specimen figured: On bark at base of black ash, Linesville, Crawford Co., June 11-12, 

 1907. O.E.J. 



7. FiSSIDENS ADiANTOiDES [Linnaeus] Hedwig 



This species differs chiefly from F. cristatiis in that the cells are larger, .012- 

 .016 X .015-. 025 mm, distinct; border none or rather indistinct: seta usually 

 longer than in F. cristatiis, about 1-2.5 cm long. The plants are often much 

 larger, 2-15 cm high, and are monoicous instead of dioicous, as in F. cristatus. 

 The two species apparently intergrade. 



