Jennings: Manual of Mosses — 16. Adi.acomniaceae 145 



the tips; leaves crowded, decurrent, erect-ascending, the margins more or less 

 revolute; costa ending below apex; cells each with a central papilla; capsule 

 somewhat arcuate; annulus 2-4-seriate, revoluble; teeth lance-linear and sub- 

 ulate-acuminate, yellow to rusty, the divisural zigzag, finely papillose, with 

 numerous articulations; inner peristome delicate, hyaline; basal membrane one- 

 half height of teeth, segments lance-subulate, gaping; cilia well developed, 

 delicate, mostly only weakly articulate. 



Nine species widely distributed; five in North America, two in our range. 



Key to the Species 



A. Autoicous; leaves strongly serrate from the middle upwards 1. A. heterostichum 



A. Dioicous; leaves merely serrulate near the apex 2. A. palustrc 



1. Aulacomnium heterostichum (Hedwig) Bryologia Europaea 



(^AnhenopteTum heterostichum Hedwig) 

 Plate XXVIII 



Rather loosely cespitose, pale to yellowish-green: stems branching by ter- 

 minal, annual innovations, the annual growth in our specimens being usually 

 about 8-10 mm, stems brown-radiculose below; leaves usually about 8-10 mm, 

 stems brown-radiculose below; leaves obovate below to oblong or elongate- 

 ovate above, often somewhat unsymmetrically inclined, the leaf plane above, 

 coarsely repand denticulate in the upper half, mostly apiculate; costa strong, 

 yellowish-brown, ending just below apex; leaf-cells incrassate, median and 

 apical rounded-quadrate, about .008-.015 mm in diameter, basal similar, quad- 

 rate to rectangular and 3:1: seta about 6-15 mm long, erect, flexuous, reddish- 

 brown, smooth, little or not at all twisted; capsule about 2.5 mm long, oblong- 

 cylindric, arcuate, inclined, reddish-brown, striate, when dry 8-plicate, tapering 

 below into a short collum: annulate; doubly peristomate; teeth inserted on the 

 capsule-rim, lanceolate, about 25-30 articulate, distinct to the base, yellowish- 

 pellucid, rather indistinctly finely horizontally striate-papillate below, seg- 

 ments of same length or a little shorter, hyaline, more or less completely 

 carinate-cleft in median portion, united in the lower third with the cilia into a 

 basal membrane: cilia 3 (2), somewhat shorter, somewhat articulate; spores 

 pellucid-yellowish, not distinctly papillose, about .010-.014 mm; mature in 

 May to June; operculum convex, obtusely short-rostrate; calyptra long-rostrate, 

 cucullate. 



On shaded, moist, earthy banks, bases of trees, etc., Japan and in North 

 America from Ontario to Minnesota, and Texas to Florida. 



Known from the following counties: Beaver, Bedford, Butler. Cameron, Clarion, Clear- 

 field, Erie, Fayette, Green, McKean, Somerset, and Washington. Specimen figured: Ohio 

 Pyle, Fayette Co., J.A.S. June 15, 1902. 



2. Aulacomnium palustre (Weber and Mohr) Schwaegrichen 



(Hypnum palustre Weber and Mohr) 

 Plate XXVIII 

 Robust, densely cespitose mosses of bogs and moist places on soil or rotten 

 wood; tufts often 2-3 inches deep, light yellowish-green above, below darker 



