340 A MANUAL OF MOSSES 



9. Brachythecium rivulare (Bruch) Bryologia Europaea. 

 (Hypiutm rh'itlarc Bruch; B. flaresccns Kindberg). 



(Plate LI) 



Robust, cespitose in wide and thick mats, pale golden 

 green, shining, rigid : stems hard and woody, prostrate, fili- 

 form, leafless when old; branches irregular on the ascending 

 or sub-erect and somewhat dendroid secondary stems which 

 usually reach a height of 3 or 4 cm. ; stem-leaves lance-ovate, 

 rather regularly imbricate when dry, erect-spreading or more 

 open when moist, rather distant, broadly ovate, abruptly short- 

 acuminate or acute, concave, decurrent, plicate, denticulate, 

 reaching about 1.8-2.5x1-0-1.4 mm.; branch-leaves similar to 

 the stem-leaves but usually wider, ovate to lance-ovate, decur- 

 rent, about 1.5-3.X1-1-5 mm., quite concave, dentate above, 

 the margins plane or reflexed below, often somewhat plicate ; 

 median leaf-cells linear, about 10-15:1, prosenchymatous with 

 rounded ends, rather incrassate, the apical shorter, the basal 

 abruptly laxer, shorter, wider, the median basal usually with 

 incrassate and porose walls, the alar abruptly differentiated, 

 more or less enlarged, inflated, hyaline to orange-pellucid, 

 forming distinct and widely decurrent auricles ; costa often 

 forking, reaching to the middle or above; seta 1.5-2.5 cm. long, 

 strongly papillose throughout, castaneous ; capsule castaneous, 

 turgid- to oblong-ovate, about 2-3x1 mm., more or less 

 arcuate, inclined to more or less horizontal ; lid conic-acumi- 

 nate ; annulus 2-seriate ; exothecial cells at rim small and 

 rounded, below larger and rounded-oblong ; peristome-teeth 

 castaneous below, apically hyaline and papillose, basally con- 

 fluent, strongly trabeculate, distinctly margined by the pro- 

 jecting edges of the cross-striolate dorsal lamellae; segments 

 nearly as long, carinately split and gaping, yellowish, the basal 

 membrane about one-half as high, cilia 2 or 3, nodose, slender, 

 about as long as the segments; spores smoothish, the walls 

 somewhat incrassate and greenish-brown, about .016-.020 mm., 

 maturing in fall or early winter. 



On wet rocks in or at the margin of streams, swamps, 

 or in wet places in ravines, usually where often submerged ; 

 Europe, Asia, and from Canada to Missouri and North Caro- 

 lina. Rather common in our region. 



Allegheny 



Beaver 



Cambria 



Moon Township, April, 1002. T. A. S. 

 Beaver Falls, May 11. 1907. O/E. J. 



T. P. James. Cresson. (Porter's Cata- 

 logue). 



Crawford : Pymatu'ning Swamp, near Linesville, May 



10-11,1906. O. E. J. (Figured). 

 Fayette : Ohio Pyle, June 14, 1908. O. E. J. 



