Leptohymenium Schwägrichen, Sp. Musc. Frond. Suppl. 3(1)(2): plate 246c. 1828.
Greek lepto, thin, and hymen, membrane, in reference to the endostomial basal membrane
J. R. Rohrer
Plants prostrate [often with ascending-arching innovations]; growth monopodial or sympodial. Stems irregularly branched to regularly 1--2-pinnate; paraphyllia absent. Stem leaves loosely erect-spreading to squarrose, broadly ovate to ovate-lanceolate, sometimes plicate, not rugose, decurrent; margins serrulate to serrate distally, nearly entire proximally; apex obtuse to acuminate; costa double, extending 1/4--1/2 leaf length; cells smooth or prorulate; alar cells few and small [conspicuously enlarged and lax]. Branch leaves erect to spreading, ovate to elliptic-lanceolate, slightly decurrent; alar cells slightly differentiated. Capsule erect; operculum high-conic or obliquely rostrate; exostome teeth smooth proximally on exterior surface; endostome segments short, narrow, imperforate; cilia absent.
Species 3 (1 in the flora): montane in warm-temperate to tropical regions, Southern Appalachians; mountains of Mexico and se Asia.
Generic concepts of Leptohymenium have varied greatly, but a constant critical character has been the erect, elongate capsules. The genus is used here in the restricted sense of V. F. Brotherus (1908, 1925) and J. R. Rohrer (1985b) for species that exhibit a sympodial growth form.
Crum, H. A. and L. E. Anderson. 1967. The status of Hylocomium splendens var. tenue. Bryologist 70: 98--101.
Brotherus, V. F. 1908. Musci. In: H. G. A. Engler and K. Prantl, Die natürlichen Pflanzenfamilien, ed. 1. Leipzig.
Brotherus, V. F. 1925. Musci. In: H. G. A. Engler and K. Prantl, Die natürlichen Pflanzenfamilien, ed. 2. Leipzig.
Buck, W. R. 1997. Schofieldiella (Hylocomiaceae), a new genus for an old species. J. Hattori Bot. Lab. 82: 39--46.
Crum, H. A. and L. E. Anderson. 1981. Mosses of North America. New York.