Jennings: Manual of Mosses — 5. Pottiaceae 81 



Cosmopolitan on damp limestone rocks and boulders, but rare in our 

 region. 



Bradford Co.: On moist shaly limestone cliff. June 25, 1935. S. K. Eastwood. 

 Fayette Co.: On wet cliff, one mile up Meadow Run, Ohio Pyle, C. M. Boardman, 

 lune 23, 1940. Lawrence Co.: Gorge near Rock Point, June 26, 1909 (figured). 

 Sterile. O.E.J. 



2. Gymnostomum aeruginosum Smith 



(G. TUpestre Schleich) 



Forms dense cushions; stems slender, branched, 1 to 3 or 4 or occasionally 

 even to 10 cm long; leaves oblong- to linear-lanceolate, about 1-1.5 mm long: 

 capsule thin-walled, brownish; spores about .010-. 012 mm in diameter, mature 

 in summer. 



On moist limestone rocks, from southern Canada through eastern United 

 States in Texas 



Huntingdon Co.: Spruce Creek, T. C. Porter. 



4. Hymenostylium Bridel 



Dioicous: densely and deeply cespitose, green to rusty or yelIowish-['reen: 

 stem densely foliate, sparsely radiculose, without a central strand, triangular in 

 cross-section; leaves erect spreading, rarely squarrose-recurved, when dry in- 

 volute, sometimes somewhat twisted when dry, not crisped, more or less 

 carinate, elongate-lanceolate, acuminate; costa mostly ending below the apex; 

 laminal leaf-cells thick-walled, smooth or papillose: seta long, erect; capsule 

 erect, symmetric, obovate, firm, when empty smooth and pyriform; peristome 

 none; lid obliquely long-rostrate from a broad base, remaining attached to the 

 columella and deciduous thus attached; calyptra cucullate, covering about 

 half of the urn. 



A widely distributed genus of about 25 species, occurring mainly on cal- 

 careous rocks; 8 species in North America; only one occurring in our region. 



1. Hymenostylium recurvirostrum (Ehrhart, Hedwig) Lindberg 



(^Gymnostomum curvirostrum Bridel; Weisia curvirostris Mueller; 

 Gymnostomum recurvirostrum Hedwig 1801) 



Plate XVI 



Closely cespitose, 2-4 cm high, bright green above, darker and more or less 

 ferruginous below: leaves little or not at all twisted when dry, erect to recurved- 

 spreading when moist, narrowly lanceolate acuminate, 1-1.5 mm long, apex 

 acute, base sub-clasping, margin entire but papillose, as are also the entire 

 upper and lower surfaces of the lamina and costa, one or both lower margins 

 recurved; costa strong, vanishing just below the apex, at base occupying about 

 one-eighth the entire width of the leaf; upper leaf-cells rounded to sub-quad- 

 rangular, the lower towards the costa becoming elongate-rectangular: seta 8-10 

 mm long, lustrous, castaneous; capsule about 1 mm long, rounded ovate, lus- 

 trous, castaneous, widest towards the mouth, when dry and empty decidedly 



