324 A MANUAL OF MOSSES 



above when dry ; capsule yellowish, about 2 mm. long, cylindric 

 from a tapering neck, inclined, arcuate, smooth, but when dry 

 and empty somewhat striate; lid conic, acuminate to sub- 

 rostrate, about one-half as long as the urn; peristbme-teeth 

 bright orange at base, pale above, lance-subulate, confluent at 

 base, closely trabeculate, the dorsal lamellae finely cross- 

 striolate; segments slender, about as long as the teeth, nar- 

 rowly carinately gaping, the basal membrane about one-third 

 as high, the cilia very slender, about as long as the segments, 

 nodose, usually 3 in number; exothecial cells moderately in- 

 crassate, small and quadrate at rim, larger and oblong-rec- 

 tangular to rounded-hexagonal below; annulus large, re- 

 voluble, 2-seriate; spores pale yellowish, smooth, rather thin- 

 walled, .006-,010 mm., mature in mid-summer. 



On humus, rocks, rotten logs, etc., in woods; Europe, 

 Asia, northern Africa, and from southern Canada to Alabama 

 and from Alaska to Oregon. Probably more common in our 

 region than the localities here enumerated would indicate. 

 Allegheny : Panther Hollow, Schenley Park, Pitts- 

 burgh, November 25, 1905, and Wildwood 

 Road Hollow, June 11, 1908. (Figured). 

 O. E. J. ; Wildwood Road PIollow, No- 

 vember 19, 1908. O. E. J. and G. K. J. 

 Crawford : Linesville, May 12, 1908. O. E. J. 



Westmoreland : "Shades," near Blackburn, June 13, 1908. 



O. E. J. 

 McKean : IMarilla Brook, Bradford, October 22 and 



November 16, 1896, D, A. B. 



4. Plagiothedum denticwlatum [Linnaeus] Bryologia Europaea. 



(Hypnuin denticulaUun Linnasus). 



(Plate XLVni) 



Variable, in flattened tufts of a pale and lustrous green,, 

 moderately robust, the more or less ascending and elongate 

 branches complanate; leaves rather close, complanate and sub- 

 distichous, rather spreading, when dry little changed, glossy,. 

 2-3 mm. long, sub-concave, oval to lance-oblong, shortly and 

 sometimes almost apiculately acute, usually slightly denticu- 

 late at the apex, the lower margins entire and often narrowly 

 recurved, the base narrowed to a rather wide and strongly 

 decurrent insertion ; costa thin, variable, usually short and 

 double, sometimes forked and reaching almost to the middle, 

 sometimes none; median leaf-cells rhomboid-hexagonal, rather 

 large, about 10-15:1, about .010-.015 mm. wide, thin-walled, 

 chlorophyllose, gradually becoming laxer, pellucid, and more 

 or less rectangular at base, the alar more hyaline, sub-rec- 

 tangular, sub-inflated, and still somewhat larger but not form- 



