XX. PTEROGONIUM Swartz, Disp. Syst. Musc. Frond. Suec.: 26.1799 * [Greek pteron, feather, wing, fin, and gonio, angle, corner, possibly alluding to the papillae projecting from the cell ends]
Leaves broad, acute and serrulate, with costa absent, or if present, double and short (i.e., ending before leaf middle). Laminal cells papillose distally by projecting cell ends on abaxial surface.
Species 3 (1 in the flora): temperate regions of North
America, South America, Europe, Africa,
1. Pterogonium gracile (Hedwig) Smith, English Botany 16: 1085. 1802
Pterigynandrum gracile Hedwig, Sp. Musc. Frond., 80. 1801
Plants forming loose coarse mats; dull yellow-green to brownish green. Stems 1.5--8 cm, prostrate; branches 0.5--2 cm, numerous, often closely pinnate, appearing fascicled, and secund-ascending, julaceous with strongly attenuate tips, sometimes with elongated flagelliform tips; paraphyllia absent. Leaves closely imbricate when dry, erect-spreading when moist; ovate, 0.5--2 x 0.25--1.2 mm; base cordate, slightly decurrent; proximal margin serrulate and inflexed, distal margin serrate and plane; apex acute, concolorous; costa absent or short and double, ending before midleaf. Laminal cells linear-rhomboidal, 15--46 x 5--8 \um, shorter near apex; thick-walled, prorate, especially in distal region of leaf; alar cells numerous, oblate to rounded, 6.5--10 \um, strongly differentiated, extending halfway up the margins. Sexual condition dioicous; perichaetia acicular in axils of branches, perichaetial leaves imbricate, elongate acuminate, sheathing at base, 2.5--3 x 0.7--0.8 mm, paraphyses 0.6--0.8 mm. Seta reddish brown, 8--12 mm, twisted, smooth. Capsule exserted, erect and symmetric, light brown, cylindric, 2--3 mm, smooth; annulus deciduous, 2--3 cells thick; operculum conic, 0.4--0.5 mm; peristome double, pale; exostome teeth 16, erect, linear-lanceolate, 0.3--0.4 mm, base horizontally striolate, distally with vertical or oblique lines, weakly papillose at tips; basal membrane low, endostome segments linear, 0.3--0.4 mm, weakly papillose; cilia absent. Calyptra not seen. Spores round, 11--18 \um, papillose, brown.
Capsule maturity not seasonal. Forested mountains, rocks and boulders, trunks and bases of hardwood trees, rarely on soil; 0--1100 m; B.C.; Calif., Oreg., Wash.; Brazil; Europe; sw Asia; Africa.
J. Podpěra (1954) reported Pterogonium from
Grout, A. J., 1928--1940. Moss Flora of
Podpěra, J. 1954. Conspectus Muscorum Europaeorum. Praha.
Rasmussen, L. 1975. The bryophytic epiphyte vegetation in
the forest, Slotved Skov, northern