268 American Midland Naturalist Monograph No. 6 



concave, lance-ovate, slenderly long-acuminate, non-decurrent, more or less 

 sharply serrate at the apex, the margin often narrowly recurved below; costa 

 obsolete, or very short and double; perichaetial leaves gradually long-acumi- 

 nate, serrate at apex; median leaf-cells linear-flexuose, the basal yellowish or 

 brownish, shorter, wider, the alar consisting of a group of 4 to 8 hyaline or 

 colored, much inflated and enlarged cells forming a group bordered above by 

 a few sub-quadrate and smaller cells: seta about 1.5-2 cm long, lustrous, cas- 

 taneous, somewhat sinistrorse; capsule oblong-oval, slightly curved, obliquely 

 inclined to almost horizontal, the urn about 3-4:1, about 1.5-2 mm long, light 

 castaneous, the tapering base darker, the urn when old strongly arcuate; annu- 

 lus present; lid conic and together with the slender beak about one-half the 

 length of the urn; peristome hypnoid, the teeth large, strongly trabeculate, the 

 divisural faint, the thin dorsal lamellae transversely papillose-striolate; segments 

 about as long as teeth but usually not splitting, the basal membrane about two- 

 fifths as long, the cilia usually one, sometimes two, slightly appendiculate, 

 somewhat shorter than the segments; spores .016-.018 mm, medium-walled, 

 granulose, brownish, mature in late fall, the capsules often remaining in good 

 condition until early spring: dioicous. 



On soil, humus, bases of trees, logs, etc., in moist woods, mainly in moun- 

 tainous or hilly regions; from Newfoundland to Manitoba and south in the 

 mountains to Georgia. 



Common in our region. Known from eleven counties in western Pennsylvania and 

 probably occurs in all, although most abundantly collected m the southwestern counties. 

 Specimen figured: As to old capsules and peristome, Ohio Pyle, Fayette Co., May 30-31, 

 1908. O.E.J. As to other figures, Ohio Pyle, Sept. 1-3, 1906. O.E.J. & G.K.J. 



11. Stereodon delicatulus (James) Brotherus 



(Hypnum laxepatulum Lesquereux and James; Rhynchostegium delicatulum 



James; Sematophyllum delicatulum E. G. Britten; Rhapidostegium 



deliculatum Paris; Brotherella delicatula Fleischer) 



Small, depressed cespitose, dark green, scarcely lustrous: stems slender, 

 prostrate, subpinnately branching; leaves rather open, mostly falcate-secund, 

 two- ranked, sharply serrulate towards the apex; costa none or very short and 

 double; leaves concave, ovate, narrowed into a long acumination; a few of the 

 extreme alar cells much enlarged and inflated as in S. recurvans, colored or 

 hyaline, bordered by a few sub-quadrate and smaller, the median linear-flexu- 

 cus, prosenchymatous; perichaetial leaves non-plicate, sharply serrate above: 

 seta shorter than in S. recurvans; capsule about 1-1.5 mm long, ovoid-oblong, 

 almost erect and only slightly curved, about 2-3:1, urn about equalled in length 

 by the slenderly long-rostrate lid; peristome hypnoid, segments entire, cilia 

 usually one or two; spores mature in late fall. 



On rotten wood, or soil, or at the base of trees, mainly in the mountains 

 from New England to Alabama. 



Rare in our region. McKean Co.: Bradford. D. A. Burnett. (Porter's Catalogue). 



