OF WESTERN PENNSYLVANIA 233 



very short and thin, forked or double, rarely single and reach- 

 ing to the middle of the leaf; cells narrow to rhombic-hexa- 

 gonal, strongly and sharply dorsally papillose, basal cells wider 

 and longer, alar quadrate in several series : inner perichsetial 

 leaves thin, broadly lanceolate, sheathing, acute, the margins 

 entire and plane: seta 8-15 mm. long, red or yellow-red, drying 

 twisted; capsule erect, mostly symmetric, cylindric, yellow to 

 brown : annulus 2-seriate, narrow ; peristome inserted near the 

 mouth ; teeth lanceolate, confluent at the base, yellowish, be- 

 low transversely and obliquely striate, above smooth, distantly 

 articulate, non-trabeculate ; inner peristome hyaline, smooth, 

 with quite low basal membrane, the segments very narrow, 

 short, or sometimes almost as long as the teeth ; cilia none ; 

 spores .010-.018 mm. ; lid conic, shortly and mostly bluntly 

 rostrate. 



Only two species: P. papillosum in British Columbia, and the 

 following : 



1. Pterygynandrum filiforme [Timm] Hedwig. 



(Lcskcu cylindrica Bridel). 



On bases of trees and on rocks, in woods, widely dis- 

 tributed in the Northern Hemisphere, in Xorth America, ex- 

 tending from Greenland to British Columbia and southwards 

 to the northern United States. Occurs in the Pocono region 

 of Eastern Pennsylvania and, possibly, will be found in the 

 northern or northeastern part of our region. 



The generic description will readily enable one to differ- 

 entiate this species from other mosses in our region. 



Family XXIX. FABROXIACEAE. 



Autoicous or dioicous : slender to very slender, weak, ces- 

 pitose, mostly bright or light green, mostly lustrous: stem 

 without central strand, weak, creeping, thin, with red, fascicu- 

 late radicles; the secondary stems densely-leaved, simple or 

 branched, erect; leaves 5~8-seriate, drying appressed, spread- 

 ing when moist, rarely secund. more or less concave, uni- 

 stratose, non-decurrent, ovate to lanceolate, non-bordered, 

 non-plicate ; costa simple, delicate and short ; rarely ecostate ; 

 median leaf-cells mostly prosenchymatous, smooth, mostly 

 thin-walled, towards the basal angles quadrate to rectangular: 

 capsule exserted, erect, symmetric, oval to sub-cylindric, dry- 

 ing often longitudinally wrinkled and constricted below the 



C"^ <-T* 



mouth, the collum short and thick; peristome deeply inserted, 

 single or double : teeth plane, distantly articulate, non-lamel- 

 late, in our genera non-bordered, teeth rarely none ; inner 



*^? * 



peristome none or consisting generally of subulate segments : 

 lid broad, mostly conic and rostrate; calyptra cucullate. naked, 

 smooth, small, fugaceous; spores small. 



