198 American Midland Naturalist Monograph No. 6 



rectangular or hexagonal, only in middle of base oblong and pellucid: seta ?--4 

 mm, thin, drying twisted, reddish or yellowish, smooth; capsule erect, oval, 

 smooth, brownish, broadly annulate; peristome-teeth basally confluent, lance- 

 linear, yellowish, distantly articulate, split apart above, the ventral layer 

 broader, hyaline, non-trabeculate, but with papillae-like irregular processes; 

 inner peristome smooth, the basal membrane very low, with no segments nor 

 cilia; lid conic, obliquely short-rostrate; calyptra inflated-cucullate, furnished 

 with a few long, erect hairs; spores .020-.025 mm, papillose. 



About 20 species, mostly living on tree-trunks, rarely on rocks; one species 

 occurring in North America and reaching our region. 



1. Haplohymenium triste (Cesati) Kindberg* 



{Leskea tristis Cesati; Anomodon tristis Suilivant) 

 Plate XXXVIII 



Small, very slender, dull dirty-green, loosely, thinly, and intricately ces- 

 pitose: stems prostrate, sometimes pendent, branching with irregularly or pin- 

 nately arranged branches; branchlets erect or curved-ascending; leaves about 

 0.5-0.8 mm long, appressed when dry, more or less squarrose-spreading when 

 moist, mainly lanceolate from an ovate-base, concave, sub-clasping, crenulate 

 on the plane margins by the large and protuberant cells, apically acute to 

 short-apiculate or obtuse, the apex of the leaf very often broken oflF in the 

 dried specimens; costa slender, ending in the middle of the leaf; median leaf- 

 cells oblong-rectangular, about .011-.014 mm in diameter, thin-walled, pellucid, 

 the upper more or less rounded-hexagonal, the lower marginal transversely 

 oblong-hexagonal, the lower median often radiating from the basal part of 

 the costa in a characteristic manner: capsule unknown: leaf -cells turgid and 

 bearing several large papillae on each surface. 



On bases of trees and on steep, sunny rocks; Europe, Asia, and, in the 



eastern United States. In the Lesquereux and James Manual the habitat is 



stated as particularly on the Hornbeam. 



Rare in our region. Clearfield Co.: T. P. James. (Porter's Catalogue). McKean 

 Co.: Gates Hollow, Bradford, July 8, 1895. D.A.B. (figured). 



4. Anomodon Hooker and Taylor 



Dioicous: more or less robust, stiff, loosely cespitose, bright to blue-green, 

 dull, later yellowish to brownish, the mats mostly ochraceous inside: stem far- 

 creeping, stoloniform, small-leaved, radiculose, bearing ascending to erect, 

 often basal ly-stoloniferous secondary stems; all leafy shoots having rather uni- 

 form leaves, the branches sometimes flagelliform; foriage-leaves 5-seriate, 

 dense, rarely secund, when dry mostly imbricated, little different when moist, 

 Ungulate from a broadly ovate or oblong and little or not at all decurrent 

 base, or the upper part lanceolate to subulate, margins plane and entire; costa 

 strong, smooth, mostly ending below the apex; median leaf-cells rounded- 

 hexagonal, on both sides densely papillose with one- and two-pointed papillae, 

 rarely unipapillose over the lum.en, only the median basal elongate, smooth, 



* Perhaps better included in the genus Anomodon. 



