Jennings: Manual of Mosses — 7. Grimmiaceae 99 



A. Upper leaf-cells elongate; shoots appearing nodose with short lateral branchlets D 



B. Leaves lingulate; leai-apex broad and rounded 1. R. aciculare 



B. Leaves lanceolate-acuminate C 



C. Leaf-apex hyaline-acuminate 2. R. microcarpum 



C. Leaf-apex obtuse, not hyaline 3b. R. heterostichum var. gracilescens 



D. Leaf-apex acute, not hyaline; seta 4-5 mm long (R fasciculart) 



D. Upper leaves with hyaline points; seta 4-10 mm long 



3a. R. heterostichum var. ramulosum 



1. Rhacomitrium aciculare [Linnaeus] Bridel 



(Dicranum aciculare Hedwig) 

 Plate XVIII 



Cespitose in coarse tufts, dark dull green to blackish; stems long, up to 6 

 or 8 cm long, stout, branching by short innovations, radiculose below; leaves 

 erect-spreading, stiffly imbricate when dry, large, up to 1 mm wide by 2.5 mm 

 long, broadly ovate-oblong, usually somewhat plicate at the base, the margin 

 usually revolute, the ape.x broadly obtuse, denticulate to entire, non-hyaline, 

 the upper margin usually thickened; costa strong, ending below apex; leaf-cells 

 densely yellowish-pellucid, incrassate, sub-papillose, the upper sub-quadrate to 

 rounded-hexagonal and in two layers at the margin, the basal elongate-rectan- 

 gular to linear, markedly sinuose-incrassate, at the margin sub-quadrate, the 

 alar a little larger, quadrate: seta erect, straight, about 10-12 mm long; capsule 

 dark brown, erect, oblong-cylindric to elliptic, smooth, with narrow mouth; 

 peristome-teeth cleft to below the middle into 2 or 3 unequal divisions; lid 

 aciculate-rostrate or subulate, almost as long as urn; calyptra smooth, long- 

 rostrate, mitrate, lobed, covering only the top of capsule; annulus rather large, 

 revoluble; spores mature in spring; fruit rarely found. 



On wet, shaded, non-calcareous rocks in hilly or mountainous country, in 

 Europe, Africa, and, in North America, from Alaska and Labrador south to 

 California and Alabama. Occurs in northern West Virginia and Pennsylvania. 



Now known from Butler, Cambria (Porter), Clearfield, Fayette, Somerset, and West- 

 moreland counties. Specimen figured: Ohio Pyle, Fayette Co., in crevices of rock along 

 the river near the falls. Sept. 1-3, 1906. O.E.J. &C G.K.J. 



2. Rhacomitrium microcarpum (Hedwig) Bridel, not Schrader 



{Rhacomiirtum sudeticiim Bryologia Europaea; Trichostomum microcarpum 

 Hedwig; R. heterostichum var. sudeticnm ( Funck ) 



Loosely cespitose, dull or yellowish-green above: stem slender with ascend- 

 ing branches, 2-5 cm high; leaves divaricately spreading, erect when dry, nar- 

 rowly lanceolate, linear-acuminate, apex hyaline, denticulate, margin more or 

 less bistratose above, usually revolute below; costa strong, ending in apex; 

 basal leaf-cells linear, sinuose, incrassate, upper leaf-cells rounded-quadrate: seta 

 short, light-colored, often curved or flexuose; capsule relatively very small, 

 elliptic, pale brown, thin-walled; annulus large, revoluble; peristome-teeth 

 brownish, irregularly divided; lid conic-rostrate, shorter than the urn; spores 

 mature in spring. 



On wet rocks or cliffs, principally granite or gneiss, Europe, Asia, and, in 



