OF WESTERN PENNSYLVANIA 253 



pinnately branched; branchlets short and slender, usually 

 about 2-3 mm. long, smooth, paraphyllia present ; stem-leaves 

 bioadly cordate-deltoid, acuminate, about 0.5-0.6 mm. loner, 



* C* ' 



margins plane, finely papillose-denticulate ; branch-leaves 

 ovate-cordate, smaller, shorter acuminate, both kinds of leaves 

 concave, erect-spreading; costa pellucid, broad, about three- 

 fifths to four-fifths as long as the leaf; median leaf-cells 

 rounded-hexagonal, minute, with 2-5 small bead-like papillae 

 on each surface, incrassate, rather obscure, the basal median 

 oblong, paraphyllia numerous, linear to ovate, more or less 

 branched, occurring on both stem and branches ; inner peri- 

 chsetial leaves elongate-lanceolate, filiform-acuminate, some- 

 what longitudinally plicate: capsule sub-erect, about 1.3-1.5 

 mm. long, rather thin-walled, when old and empty more or 

 less w r rinkled, urn cylindric, straight or slightly curved, more 

 or less twisted when old, the seta about 1.5 cm. long; lid conic- 

 rostrate, curved upward : annulus large ; exothecial cells rather 

 thin-walled, mainly quadrate to rectangular; peristome-teeth 

 knee-subulate, shallowly inserted, castaneous and transversely 

 striolate below, hyaline and papillose above, lamellate and 

 trabeculate ; segments nearly as long as teeth, carinately par- 

 tially split, the basal membrane about two-fifths as high, the 

 cilia usually three, nodose ; spores medium- walled, castaneous- 

 pellucid. papillose, about .010-.013 mm., mature in fall and 

 winter; autoicious. 



On the bases of trees and on stones in woods ; from On- 

 tario to Missouri, eastward to the Atlantic Ocean and south- 

 ward to North Carolina. Rare in our region. 



McKean : On base of trees, Rutherford, August 4, 



1897, Bradford, October, 1897; Gates Hol- 

 low', July 28, 1895, and Limestone Creek, 

 Bradford, October to December, 1896. D. 

 A. B. (Figured). The last named speci- 

 men issued with Grout's No. 134, in part, 

 North American Musci Pleurocarpi. 



9. HAPLOCLAD1UM (C. Mueller) C. Mueller. 



Autoicous : slender, forming mats, yellowish-green to 

 brownish-yellow, dull : stems creeping, elongate, with brown- 

 ish rhizoids, variously pinnate with branches mostly ascend- 

 ing, julaceous, short, obtuse and simple, or somewhat longer, 

 acute and pinnate with scattering short branchlets ; leaves more 

 or less uniform, drying appressed, sometimes weakly secund, 

 when moist erect-spreading; stem-leaves more or less doubly 

 plicate, from a more or less broadly ovate base, lanceolate to 

 lance-subulate, the margin revolute at base, the upper margin 

 indistinctly serrulate to entire ; costa strong, sometimes per- 

 current, sometimes excurrent, mostly smooth ; cells more or 



