Jennings: Manual of Mosses — 2. Dicranaceae 51 



2. DiTRlCHUM PUSILLUM (Hedwig) E. G. Britton 

 {Leptotrichum pufillitm Hampe; Ditnchum tortile Brockmueller ) 



Plate X 



Cespitose, yellowish-green, rather dull: stems short, about 5-10 mm high, 

 erect or erect-ascending from a radiculose base, mostly simple, reddish; leave^ 

 about 2.5-3.5 mm long, closely appressed-erect to somewhat spreading, usually 

 somewhat secund or twisted, gradually lance-subulate and canaliculate from ai: 

 ovate-lanceolate concave base, margins more or less narrowly revolute, apex 

 usually denticulate; costa strong, less distinct at base, in the upper portion 

 constituting about one-third to one-half of the leaf-width, percurrent to slightly 

 excurrent; basal cells rectangular to linear-rectangular, alar not different, rather 

 thin-walled and hyaline, smooth, median smaller, mostly about 2:1, rectangular 

 to quadrate, smooth, the apical sometim.es bi-stratose; pericha:tial leaves more 

 or less sheathing, otherwise similar to the stem-leaves: seta reddish-brown, 

 shining, somewhat sinistrorse, erect, about 1 cm. long; capsule oblong to 

 oblong-cylindric, reddish to pale brown, smooth, non-sulcate, not constricted 

 below the mouth, abruptly narrowed to the seta at base, the urn about 1 mm 

 long; annulus uni-seriate; peristome single, rather low, reddish, the 16 teeth 

 cleft into linear-subulate, distinctly trabeculate, somewhat spirally twisted 

 divisions, at base united into a very low membrane; operculum conic-rostellate, 

 usually more or less oblique; calyptra cucullate, pale; spores rather thin-walled, 

 smooth, yellowish-pellucid, about .015-. 018 mm, mature in late fall or in 

 winter: dioicous. 



On clayey soil in fields, along roadsides, etc., in Europe, Asia, northern 

 Africa, and in the eastern half of North America from Labrador to the Gulf 

 States. 



On clay soil, roadside banks, etc., in Fayette, Greene, Allegheny, and southern Butler 

 counties in the extreme southwestern part of the state. Specimen figured: Keown Station, 

 O.E.J. November 14, 1909. 



3. DiTRiCHUM PALLIDUM [Schreber] Hampe 



Plate X 



Loosely cespitose, bright green; stems about 5 mm high, more or less erect, 

 or with a creeping base; leaves erect-spreading, sometimes somewhat secund, 

 from a lance-ovate base, prolonged linear-subulate, concave, channeled towards 

 the apex; costa strong, long-excurrent, denticulate tov/ards the apex; basal leaf- 

 cells laxly oblong-hexagonal, thin-walled, hyaline, up to about .015-. 017 mm, 

 the median cells gradually much smaller, rectangular, forming but a narrow 

 margin to the costa; seta erect, yellow, slender, dextrorse and fliexuous when 

 dry, about 1-2 cm long; capsule ovate-oblong, yellowish-red, ascending to 

 horizontal, somewhat unsymmetric, usually somewhat strumose at base, about 

 2 mm. long, when dry and empty sub-arcuate and irregularly sulcate; peristome 

 single, the 16 teeth bifid deeply, united at base into a very low basal membrane, 

 the prongs cylindric, nodose-articulate, finely papillose, reddish, about 0.5 mm 

 long; annulus compound, deciduous, bordered by two or three rows of small, 

 rounded, reddish-pellucid cells; spores globose, papillose, about .017 mm, red- 



