190 American Midland Naturalist Monograph No. 6 



About 30 species in temperate and warm regions; 7 species reported for 

 North America; one species in our region. 



1. PoROTRiciiUM allegheniense (Mueller) Grout 

 (Hypnum allegheniense C. Mueller; Thamnium allegheniense Bryologia Europaea ) 



Plate XXXVI 



Large, dendroidal in habit, bright to pale green, usually rising to a height 

 of 4-7 cm; leaves of the branches and branchlets up to 3 or 3.5 mm long, 

 rather lustrous and sub-plicate when dry, erect-spreading, oblong-elliptic, short- 

 pointed, concave, the base somewhat narrowed but scarcely concave, the apex 

 broadly acute, the plane margin strongly serrate above; costa strong, extending 

 to near the apex; leaf-cells incrassate, the median shortly rounded- or rhom- 

 boid-hexagonal, about 2:1, the basal becoming elongate-oblong, varying to 

 elongate-rectangular, the lower marginal and angular, scarcely wider but sub- 

 rectangular to quadrate; perichaetial leaves erect, sheathing, narrowly acumin- 

 ate: seta lustrous, of a rich castaneous color, usually about 1 cm long, smooth, 

 arcuate; rapsule oblong-cvlindric, castaneous and rarely somewhat wrinkled 

 when dry, about 2-2.5:1, about 2 to 2.5 mm long, nearly symmetric but by 

 the curving of the pedicel inclined or horizontal, sometimes curved; lid conic, 

 long- and stout-rostrate, the whole lid being about one-half to one-third as 

 long as the urn; peristome normally hypnoid, large; teeth lance-subulate, dis- 

 tinctly but finely cross-striate in at least the lower half, hyaline and papillose 

 above, castaneous-pellucid below, the dorsal lamellae and the divisural dis- 

 tinct, the trabeculae well developed; segments papillose, pale yellowish, about 

 as long as teeth, cleft carinately between the articulations; basal membrane 

 one-third as high as teeth; cilia 2-3, sub-appendiculate, almost as long as seg- 

 ments; annulus narrow, revoluble, simple; spores mature in late fall or early 

 winter, smooth, castaneous-pel'ucid, medium-walled (about .009 mm Grout) . 



On dripping rocks and ledges along streams in the hills or mountains from 

 Nova Scotia to Minnesota and south to the Gulf States. 



Cambria Co.: Cresson. T. P. James. (Porter's Catalogue). Huntingdon Co.r 

 T. C. Porter. (Porter's Catalogue). McKean Co.: On stones in or at rhe edge of 

 streams, Hedge-hog Hollow, March 18, 1894, Bennett Brook, April 9, 1893 (figured), 

 and Limestone Creek, N. Y., all near Bradford. 



Family 28. Entodontaceae 



Autoicous or diocious: slender to quite robust, mostly stiff, laxly cespitose, 

 mostly lustrous; central strand none or but few-celled; stem thickly-foliate, 

 julaceous or complanate; leaves pluri-seriate, uni-stratose, often unsymmetric; 

 costa delicate, homogeneous, never complete, or double and very short, or 

 none; leaf-cells mostly prosenchymatous, the alar differentiated, being quadrate 

 or transversely widened: capsule exserted, mostly erect and symmetric, never 

 plicate; peristome mostly double, the inner rarely lacking; teeth yellow to 

 castaneous, with divisural, trabeculate, mostly papillose; segments narrow or 

 lance-subulate, often split carinately, the basal membrane low, carinate, the 



