156 American Midland Naturalist Monograph No. 6 



costa long-aristate-excurrent: seta very short, without central strand; capsule 

 immersed, obliquely ovate-conic, gibbous, without collum, mouth very small; 

 annulus present; outer peristome rudimentary or none, when present consisting 

 of 16 triangular teeth; inner peristome pale, membranaceous, 16-plaited, papil- 

 lose, short-conic; operculum small, acute-conic, falling away attached to the 

 upper part of the fleshy columella; calyptra very small, conic, glabrous. 

 A genus of about 15 species, only one in North America. 



1. DiPHYSCiUM FOLIOSUM (Hedwig) Mohr 

 {Buxbaumia foliosa Hedwig; Webera sessilis Lindberg) 



Plate XXIX 



Small, widely cespitose, very short-stemmed (1-2 mm), the general af>- 

 pearance being that of a grain of wheat sitting in a tuft of bristles: stem-leaves 

 minute, the largest being about 3 mm long, linear-oblong, obtuse, somewhat 

 concave, crisped when dry; costa broad, nearly reaching apex; perichaetial leaves 

 4-7 mm long, lance-linear, the costa one-third the width of the leaf at base, 

 brownish-yellow, excurrent as a spinulose arista which often reaches one-half 

 the whole length of the leaf, the apex of the lamina acute and entire or lacerate- 

 ciliate; cells at base of the stem-leaves and of nearly the whole lamina of the 

 perichaetial leaves hyaline, thin-walled, irregularly elongate-rectangular to 

 hexagonal, the costa in the lamina of the perichaetial leaves being bordered on 

 either side by several rows of smaller, chlorophyllose, quadrate, and somewhat 

 opaque cells, the lamina of the stem-leaves also being opaque with very small 

 round-hexagonal cells: capsule 4-6 mm high, ventricose, ovate-conic, yellowish- 

 green; operculum acute-conic; calyptra small but covering the operculum; 

 annulus and outer peristome more or less rudimentary; inner peristome conic, 

 whitish, membranaceous, papillose, 16-carinate; spores moderately thick- walled, 

 .007-.010, papillose, mature from mid-summer to early fall. 



Widely distributed in the Northern Hemisphere. In North America it 

 occurs from Alabama to Nova Scotia and Ontario, on moist shaded banks and 

 clayey hillsides, and, in our region, especially along rather bare banks along 

 paths in black oak — scarlet oak woods in the mountains. Usually associated 

 with white flecks of Cladonia lichen thalli. 



Butler Co.: Roadside bank, McKelvy School, Brady Twp., April 26, 1936. Sidney 

 K. Eastwood. Cameron Co.: Canoe Run, Lumber Twp., Sept. 1, 1935. A. M. Barker. 

 Centre Co.: Tussey Mt., Shingletown, July 15, 1909. O.E.J. Fayette Co.: Wooded 

 roadside bank, Sugar Loaf Mt., Sept. 1-3, 1906 (figured), and near Lover's Leap, Ohio 

 Pyle, Sept. 4, 1906. O.E.J. & G.K.J. Somerset Co.: Moist bank, Laurel Ridge, 2 mi. 

 s. of Miller School, Oct. 6, 1935. C.M.B. Westmoreland Co.: Roadside bank, 

 "Rachelwood," New Florence, Sept. 9, 1907. O.E.J. Alt. 2,100 ft. 



2. Buxbaumia Haller, Hedwig 



Dioicous; antheridial plants microscopic on the green protonema; arche- 

 gonial plants with a short stem, a few small leaves, and one or two archegonia 

 but no paraphyses: isolated or gregarious, annual: stem barely 1 mm high, 

 simple, with hyaline rhizoids; leaves ovate to lance-ovate, the basal portion 

 green and its cells growing out into long brown filaments during the develop- 



