72 American Midland Naturalist Monograph No. 6 



the capsule erect, oblong-oval to oblong- obovate, somewhat narrowed below 

 the mouth, smooth, brownish; operculum hemispheric-apiculate to very shortly 

 rostrate; peristome yellowish-pellucid, trabeculate, the teeth lanceolate, acumi- 

 nate; capsule walls with cells incrassate, quadrate to hexagonal; spores smooth, 

 .018-. 023 mm. Mature in autumn. 



On wet rocks from New England to Minnesota, Colorado, Texas, and 

 Alabama. 



In West Virginia on walls of Lock No. 9, Monongahela River, a short dis- 

 tance south of the West Virginia-Pennsylvania State Line, July 3, 1909. O.E.J. 



Rare in our region. Beaver Co.: Gorge of Little Beaver Creek, on sides of large 

 sandstone rocks in dashing current and often inundated, Smith's Ferry, October 1, 1910. 

 O.E.J. (On the Ohio-Pennsylvania State Line.) 



4. FissiDENS MiNUTULUS Sullivant 



(f. incurvus var. minutuliis (Sullivant) Austin) 

 Plate XIV 



Plants minute, 0.8-3.0 mm high, gregarious, green, erect: stem simple, 

 reddish; leaves 3-7 pairs, hardly imbricate, the uppermost much larger and 

 incurved-erect and up to 2.5 mm long, narrowly oblong-lanceolate, more or 

 less acute, the border narrow, ceasing below apex, widest at upper part of 

 sheath, margin entire or somewhat undulate, the sheath about one-half the 

 length of the leaf, the inferior lamina narrowing at base but hardly decurrent; 

 costa strong, ending usually a little below apex; leaf-cells incrassate, more or 

 less rounded to hexagonal, rather irregular, the basal becoming rectangular, the 

 border consisting of 1-3 rows of elongate-linear or ascending prosenchymatous 

 cells: seta reddish, smooth, erect, subflexuous, about 3-6 mm long; capsule 

 usually erect, subflexuous, about 3-6 mm long; capsule usually erect, symmetric, 

 0.7-0.9 mm long, yellowish to dark chestnut color, oval-oblong, tapering 

 abruptly at base; peristome rich red-chestnut, the teeth deeply forked into two 

 av.'I-like prongs with prominent spiral thickenings, teeth slightly inserted; spores 

 round to oblong, pellucid, pale yellow-red, smoothish, .014-. 017 mm in diam- 

 eter; operculum conic-rostrate. Mature in early autumn. 



On damp stones and rocks in shady woods or in stream beds, Europe, and 

 from eastern Canada south to the Gulf States. 



Now known from the following counties: Allegheny. Armstrong, Butler, Lawrence, 

 McKean, Warren, Washington, and Westmoreland. Figured from specimens from Mellon 

 Estate (Rachelwood), New Florence, Westmoreland Co., O.E.J. Sept. 8, 1907. 



5. FiSSlDENS EXIGUUS Sullivant 

 Plate XV 

 Plants very small, gregarious, light green: stems, in our specimens, 1-2.5 

 mm, high, erect, or ascending; leaves usually 3-5 pairs, the lower minute, the 

 upper reaching 1.5 mm long, ascending to erect, oblong-lanceolate, acute, only 

 the sheath margined, entire, the dorsal lamina narrowing to none at the base, 

 the sheath about one-half the length of the leaf; costa stout, vanishing a little 

 below apex; cells in apical lamina quadrate to hexagonal, at base of leaf be- 



