194 A MANUAL OF MOSSES 



Creek, Charleroi, April 26, 1908. O. E. J. 

 A\ estmorelancl : Hillside, May 19, 1906, and May 22, 1909. 



O. E. I. "Shades," three miles east of 

 Trafford, March 25, 1910, Chestnut Ridge, 

 above Hillside, May 23, 1908, and Sep- 

 tember 16-17, 1909. "O. E. J. and G. K. J. 



3. POLYTRICHUM Dillenius, Hedwig. 



Dioicous; antheridial flowers cup-shaped, sprouting from 

 the middle: robust, stiff, in green to bluish-green, mostly high 

 tufts ; stem with a complex central strand, rising from a sub- 

 terranean rhizome, often whitish tomentose, mostly simple ; 

 leaves dense, erect-spreading to recurved, drying stiffly erect, 

 from a sheathing scarious base elongate-lanceolate to linear- 

 subulate, non-bordered, with margin plane to involute, sharp- 

 ly serrate, the sheathing base unistratose and hyaline, at least 

 at the angles ; lamina bi-stratose except at the margin ; costa 

 narrow and flat below, above stronger, dorsally toothed to- 

 wards apex, mostly excurrent as a colored, toothed awn ; 

 lamellae erect, high, numerous, covering the costa and the bi- 

 stratose lamina ventrally; cells in the sheathing base elongate- 

 rectangular to linear, narrower marginward ; laminal cells 

 small, incrassate, quadrate-hexagonal: sporogonia solitary; 

 seta long, stiff yellowish-red to purplish, often drying flat and 

 sinistrorse ; capsule first erect, finally inclined or horizontal, 

 mostly prismatic, 4-6-angled, oblong to cubic, collum hemi- 

 spheric or disk-like, with stomata ; spore-sac free ; teeth 64, 

 with a colored axis, basal membrane colored ; operculum large, 

 conic to convex, rostrate ; calyptra cucullate and with the long, 

 shaggy hairs completely enclosing the capsule. 



About 125 species, mainly on soil in the cooler parts of 

 the globe ; 22 species in North America ; at least 5 species in 

 our range. 



Key to the Species. 



a. Exothecial cells of capsule not pitted; hypophysis not distinct; 



capsule longer than broad. 1. P. ohiocnse. 



a. Exothecial cells of capsule with large pits; hypophysis disk-like, 

 distinct with a constriction above; capsule approximately cubic. 



b. 

 b. Leaf-margin entire, broad and inflexed; marginal cell of lamellae 



not emarginate in cross-section. c. 



b. Leaf-margin sharply serrate, not inflexed; marginal cells of 



lamellae emarginate in cross-section. 5. P. commune. 

 c. Excurrent costa hyaline, long; plants low (about 1.5-2 cm.), 



simple. 2. P. piliferum. 



c. Excurrent costa red, short; plants larger, d. 



d. Stems not or but slightly tomentose; capsules oblong-tetra- 

 gonal. 3. P. juniperinum. 

 d. Stems covered below with whitish tomentum; capsules more 

 or less cubic. 4. P. alpcstrc. 



