OF WESTERN PENNSYLVANIA 303 



teeth slender, strongly trabeculate, dorsally lamellate, faintly 

 transversely papillose-striolate, margined, yellowish, confluent 

 below ; segments broad, nearly as long as the teeth, widely 

 carinately gaping, yellowish and papillose ; cilia sub-appendicu- 

 late, about as long as the segments, usually single ; the basal 

 membrane about two-fifths as high as teeth ; spores about .014- 

 .018 mm., smooth, moderately incrassate, castaneous. 



Mainly over humus, etc.. in moist, shaded woods, but oc- 

 curring in moist pastures, dry open woods, and bogs as well; 

 Europe. Asia, and from Arctic America to the northern United 

 States. Xot uncommon in the northern and central parts of 

 Pennsylvania. 



Elk : McMinn. (Porter's Catalogue). 



Huntingdon : T. C. Porter. (Porter's Catalogue). 



McKean : Rutherford Rocks, on perpendicular face 



of moist sandstone in wide mats, altitude 

 of 2000 feet. April 25, 1893 ; on decaying 

 log. West Branch Swamp, April 5, 1895, 

 and Bradley Run (Figured), all near 

 Bradford. D. A. B. 



Somerset : Allegheny Mountains, August 17, 1875. 



B. H. Patterson. 



Cameron : On ground in pine grove. Hunt's Run, 



April 29. 1893. D. A. B. 



16. PTILIUM (Sultivant) DeNotaris. 



Dioicous : robust, stiff, laxly cespitose, plume-like, yellow- 

 ish-green, in shade bright green, lustrous ; stem 5-20 cm. long, 

 ascending to erect, simple or 2-3-divided, regularly and dense- 

 ly complanately pinnate with dense complanate branches; 

 branches horizontally spreading, circinate at the apex, of near- 

 ly equal length below, rapidly becoming shorter at the apex; 

 leaves crowded, circinate to almost coiled, deeply pluri-plicate, 

 long-lance-subulate from a broadly ovate and scarcely decur- 

 rent base, plane-margined, finely serrulate above the middle ; 

 costa none, or double and short ; median leaf-cells very nar- 

 rowly linear, vermicular-prosenchymatous, smooth, the basal 

 shorter, wider often and porose, a few alar indistinctly differ- 

 entiated, quadrate to shortly rectangular: seta 3-5 cm. long, 

 tortuous, red, drying dextrorse above: capsule cernuous to 

 horizontal, arcuate, about 2 mm. long, castaneous, cylindric, 

 smooth : annulus narrow, 2-seriate ; lid dome-like, shortly 

 apiculate. 



The genus contains only 1 species, as follows: 



