OF WESTERN PENNSYLVANIA 32? 







Key to the Species. 



a. Capsules erect and symmetric or nearly so; leaves secund upwards 



and branches curved at ends. 3. R. adnatum. 



a. Capsules more or less inclined to horizontal; leaves erect-spreading 



in all directions, or somewhat secund. b. 



b. Leaves serrate, sub-orbicular. 2. R. novae-caesareac. 



b. Leaves entire or nearly so; oblong-ovate to more or less lanceo- 

 late, c. 



c. Leaves usually more than 2 mm. long. (R. maryktndicum (C. 



M.) Jaeg and Sauerb. > 

 c. Leaves usually less than 1.5 mm. long. 1. R. carolinianum. 



I. Rhaphidostegium carolinianum (C. Mueller; Jaeger. 



(Hypmim carolinianum C. Mueller; H. demissum var. carolin- 

 ianum Lesquereux and James; Seuiatophyllnm carolinianum 



E. G. Britton). 



(Plate XL VII I) 



Rather dark green, drooping-cespitose, lustrous : stems ir- 

 regularly branching, often buried in the sand and then more or 

 less leafless and with erect to ascending simple branchlets 

 about 1-1.5 cm. long; leaves imbricate, more or less secund 

 or complanate above, non-plicate, concave, lance-ovate or 

 lance-oblong, more or less sub-serrulate at apex, shortly acute, 

 the margin often rather broadly reflexed ; costa none, or faintly 

 indicated by striae ; median leaf-cells linear-flexuous, small, in- 

 crassate, about 8-10:1, towards the base shorter and broader, 

 the alar abruptly much enlarged and inflated to form a group 

 of 2-8 pellucid and hyaline or colored cells ; perichsetial leaves 

 rather closely imbricate, lance-oblong, acuminate : seta erect, 

 sinistrorse below, castaneous, about 1 cm. long; capsule curved 

 and inclined, constricted below the mouth when dry and 

 empty, the urn about 1.2-1.5 mm. long, oblong-pyriform, yel- 

 lowish ; exothecial cells rounded-hexagonal, collenchymatous ; 

 peristome orange-yellow, the teeth with distinct divisural and 

 lamellae, dorsally cross-striolate, hyaline-margined, strongly 

 trabeculate ; segments about as long, slender, rarely split, the 

 cilia 1 (or 2), about one-half to two-thirds as long as seg- 

 ments, the basal membrane about two-fifths the height of the 

 peristome; lid comparatively large, the beak oblique, subulate, 

 and about two-thirds to three-fourths as long as the urn ; spores 

 smooth, yellowish-incrassate, usually chlorophyllose, about 

 .014-.018 mm., mature in summer or early autumn. 



On w r et non-calcareous rocks, mainly in ravines in hilly or 

 mountainous districts ; Asia, and from Newfoundland south- 

 wards to Georgia. Probably not uncommon in our region. 



Allegheny : Haysville Hollow, September 20, 1908. 



O. E. J. ; on damp rocks under hemlocks, 

 Wildwood Road, November 19, 1908. O. 

 E. J. and G. K. J. 



