OF WESTERN PENNSYLVANIA 279 



radiculose, with few or no paraphyllia, usually hooked at the 

 apex; stem-leaves cordate-triangular, finely and gradually 

 acuminate, varying from erect-spreading to sub-secund; 

 branch-leaves rather narrower, more usually strongly falcate- 

 secund ; all leaves rigid, altered but little in drying, not plicate, 

 markedly decurrent, the base cordate and narrowed, the margin 

 plane or recurved at the base and closely and finely serrulate 

 from base to apex; costa strong, usually ending in the apex; 

 median leaf-cells elliptic-hexagonal to elongate rectangular, 

 mostly about 3-6:1, usually obtuse at the ends, the alar abrupt- 

 ly inflated, hyaline or colored, forming well-defined auricles 

 of sub-rectangular cells, these cells reaching to the base of the 

 costa or nearly so; perichaetial leaves erect, strongly costate 

 but scarcely plicate, denticulate : seta long, flexuous, up to 3-5 

 cm. long, flattened and twisted; capsule sub-cylindric, rather 

 turgid, arcuate, when dry and empty constricted below the 

 mouth and more or less sulcate ; lid conic, acute, or apiculate ; 

 peristome hypnoid, the segments more or less cleft carinately, 

 cilia 2 or 3, nearly as long as the segments and teeth ; annulus 

 simple, narrow ; spores mature in spring. 



On earth, stones, etc., in or near springs, streams, or 



swamps, principally in calcareous districts ; Europe, Asia, 



northern Africa, and, in North America, from the Arctic re- 



- gions south to the northern United States. Rare in our region. 



Huntingdon : Spruce Creek. T. C. Porter. (Porter's 

 Catalogue) . 



5. SCIAROMWM Mitten. 



Mostly dioicous : more or less robust, stiff, cespitose, dull, 

 dark green to blackish : stem long, floating, sparsely radiculose, 

 with irregularly and sometimes rather fasciculately arranged 

 branches mostly directed forwards and mostly long and simple ; 

 leaves close, spreading to secund, concave-carinate, non-plicate, 

 not at all or but slightly decurrent, ovate to lance-oblong, sub- 

 acute to acuminate, plane-margined, mostly entire, broadly and 

 thickly bordered; costa strong, ending apically in the border 

 or excurrent ; median leaf-cells chlorophyllose, strongly incras- 

 sate, rather opaque, prosenchymatous-hexagonal, 2-4(-6) :1, 

 the basal cells more lax, the alar somewhat differentiated, the 

 marginal slender, strongly incrassate, hyaline, in several 

 layers; costa ending in the border at the apex: seta 1-3 cm. 

 long, castaneous below, more yellowish above ; capsule inclined, 

 unsymmetric, oblong, when dry somewhat constricted below 

 the mouth, annulate ; peristome-teeth yellow, bordered, cross- 

 striate, apically pale and papillose, the margin step-like, tra- 

 beculse numerous; inner peristome yellowish, with high basal 

 membrane, segments keeled, narrowly carinately split, cilia 1-3, 



