228 American Midland Naturalist Monograph No. 6 



2. Pylaisia Selwynii Kindberg 



(P. intncata Bryologia Europaea; Pylaisiella intricata Grout; 

 Pylaisia Schimperi Cardot) 



Plate XXXVII 



In thin, densely interwoven mats, dark-green, glossy; rather closely and 

 regularly pinnate: branches more or less ascending to erect, usually about 

 3-4 mm long, when dry decidedly curved or hooked at the end; leaves close, 

 imbricate at the base, prominently falcate-secund, especially so when dry, 

 lance-ovate, about 0.7-1.0 mm long by about one-third as wide, rather long- 

 acuminate, sub-serrate to entire, rounded at the base, concave, the margin 

 plane and non-bordered; costa short and double, or none; median leaf -cells 

 about 6-10:1, usually .003-.004 mm wide, linear-prosenchymatous, the apical 

 i;horter and wider, the alar distinct, numerous, quadrate to transversely rectan- 

 gular, yellowish-incrassate, forming a triangular group extending up along 

 the leaf-margin to one-third the length of the leaf; perichaetial leaves similar 

 but longer, up to 2.5 mm, and more slenderly acuminate: seta about 1.5 cm 

 long, lustrous, red-castaneous, dextrorse above; capsule ovoid-oblong castane- 

 ous, about 2 mm long, about 2.5:1, erect, symmetric, small-mouthed; peri- 

 stome-teeth narrowly triangular lanceolate, closely trabeculate, the dorsal 

 lamellae narrow, numerous, finely cross-striate, pale yellow, bordered up to 

 two-thirds or three-fourths by the linear, adherent, hyaline and somewhat papil- 

 lose segments, which are usually united at the tip but widely split below; cilia 

 none; basal membrane very narrow or none; annulus 2-3-seriate, narrow; cxo- 

 thecial cells yellowish, somewhat incrassate, irregularly round-hexagonal to 

 oblong-rhomboidal, below the annulus several series being much smaller nnd 

 transversely rhomboid-oblong; lid about 0.5 mm high, conic-obtuse, often 

 somewhat oblique; spores densely chlorophyllose, densely incrassate, castaneous- 

 pellucid, papillose, about .018-. 025 mm, mature in September or October. 



On stones and bark of trees; Siberia, and from Canada to Florida. 



Common in our region. Known from Allegheny, Butler, Clearfield, Elk, Erie, Fayette, 

 Indiana, Lawrence, McKean, Washmgton, and Westmoreland counties. Specimen figured: 

 Ohio Pyle, Fayette Co., Sept. 1-3, 1906. O.E.J, .ind G.K.J. 



3. Pylaisia subdenticula Bryologia Europaea 



(Pylaisia denticulata SuUivant) 



Intricately cespitose, glossy, yellow-green; stems creeping with erect or 

 ascending branches about 5-6 mm long; branch-leaves subfalcate, secund, erect- 

 spreading to imbricate when dry, lance-ovate, entire below, sub-denticulate 

 above, acuminate, concave, ecostate or faintly costate at base; leaf-cells Hnear- 

 rhomboidal, 6-8:1, quadrate alar cells numerous, incrassate, extending up the 

 margin: seta short, erect; capsule oblong, about 2.5-3.5 mm long, about 3-4:1, 

 erect; lid shortlv rostrate; annulus narrow; peristome-teeth lance-linear, seg- 

 ments free, basal membrane distinct, cilia none; spores about .008-. 012 mm in 

 diameter, mature in autumn. 



On bases of trees and on rocks, in woods, ranging irregularly from New 



