OF WESTERN PEXXSYLVAXIA 271 



teeth, slightly carinately split, the basal membrane about two- 

 fifths as high; cilia usually 3, pale, papillose, some of them as 

 long; as the teeth, nodose; annulus rather large, two-seriate; 

 upper exothecial cells small, rounded-hexagonal or quadrate, 

 below becoming elongate-hexagonal or oblong-rectangular ; 

 spores in late spring or early summer, somewhat incrassate. 

 castaneous, minutely roughened, about .015-.018 mm. 



On moist earth in swampy or marshy places ; Europe, Asia, 

 and probably throughout temperate North America. Fairly com- 

 mon in our region but in its smaller sizes difficult to satisfactorily 

 distinguish from A. jurat skanum. 



Allegheny : On wet woods-humus, Guyasuta Hollow, 



October 12, and October 25, 1908. O. E. 

 J. ; Kennywood, May 3, 1902, Moon 

 Township, May 18. 1902. J. A. S. 

 Center : On wet, clavey soil in Barrens near Scotia, 



Ju!y 14, 1909.' O. E. J. 

 Crawford : Linesville, Pymatuning Swamp, June 12, 



190" O. E. J. 



Fayette Ohio Pyle, June 11, 1908. O. E. J. 



Lawrence New Castle, 1906. Miss Susan Gageby. 



McKean West Branch Swamp, November 15, 1899. 



D. A. B. 

 Washington : On damp roots of black walnut, Hanlin, 



May 21, 1908. O. E. J. 



Westmoreland : On wet rocks at edge of stream, Hillside, 



May 19, 1906, and Garrett Farm, near 

 Trafford, August 21, 1910. O. E. J. 



7. Amblystegium riparium [Linnaeus] Bryologia Europsea. 



(Hypnum riparium Linnaeus; H. laxifolium Bridel ; Stcreodon 

 riparium Mitten). 



(Plate XXXVIII) 



Loosely cespitose, yellowish-green, the flat tufts soft: 

 stems creeping, sub-pinnate, the branches usually 2 or 3 cm. 

 long, spreading to horizontal, the stems sometimes floating and 

 reaching; a lengfth of 8 or 10 cm. ; stem-leaves 2-4 mm. lono-, 



O O *J 



rather widely spreading or almost squarrose both wet and dry, 

 often somewhat complanate, at tips of branches more or less 

 secund, widely lance-ovate to oblong-lanceolate, gradually 

 tapering to a fine, flat, non-channeled acumination, shortly de- 

 current, rounded at base, non-auriculate, somewhat excavate ; 

 branch-leaves similar but smaller, all leaves entire and plane - 

 margined ; costa fairly strong, reaching from one-half to three- 

 fourths the length of the leaf; median leaf-cells linear-rhom- 

 boid, prosenchymatous, usually 8-12(-15) :1, thin-walled, 

 chlorophyllose, towards the base lax and sub-rectangular, at 



