340 A MANUAL OF MOSSES 



9. Brachythecium rivulare (Bruch) Bryologia Evuopaea. 



(Hypnum rivulare Bruch; B. flavescens 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 1.5-3X1-1-5 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 

 rotmded, 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 : Moon Township, April, 1902. J. A. S. 



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



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



logue) . 



Crawford : Pymatuning Swamp, near Linesville, May 



10-11.1906. O.E.J. (Figured). 



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



