Eulacophyllum

• Authority

  Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.

• Family

  Stereophyllaceae

• Scientific Name

  Eulacophyllum

• Description

  Genus Description - Plants relatively small, in lustrous, light- to yellow-green, mostly thin, ± flat, tightly attached mats. Stems creeping, simple or sparingly and irregularly branched, somewhat complanate-foliate; in cross-section without a hyalodermis, with small firm-walled cells surrounding large thin-walled cells, central strand absent; rhizoids smooth; pseudoparaphyllia filamentous; axillary hairs with a single short brown basal cell and 2 hyaline distal cells. Stem and branch leaves similar, mostly distant, ± stiff, erect-spreading when dry or moist, complanate, oblong-lanceolate to oblong-ovate, sometimes Ungulate, cultriform, acute to obtuse, often asymmetric, flat or concave, not decurrent; margins serrate to serrulate above, serrulate to entire below, plane; costa single, projecting at apex as a small spine; cells long-rectangular to long-hexagonal with thickened, blunt ends, ca. 10-15:1, often appearing prorulose but smooth or nearly so, firm-walled, not porose, becoming shorter in extreme apex; alar cells usually distinctly differentiated, quadrate to rectangular, small, with many on one side of costa and few on other, sometimes with few on both sides of costa, extending across adaxial surface of the costa, collenchymatous. Asexual propagula none. Autoicous, but rarely fertile; perigonia scattered along stems, bracts lanceolate-ovate short-acuminate, ecostate. Perichaetia along stems, especially at bases; leaves ovate-lanceolate, acuminate, margins erose at shoulders, costa none; cells longer than in vegetative leaves, smooth, firm-walled. Setae elongate, smooth, orange to reddish brown, straight or flexuose; capsules cernuous, somewhat arcuate, ellipsoidal or ovoid, not plicate; exothecial cells quadrate to short-rectangular, thick walled, somewhat collenchymatous; annulus differentiated; operculum rostrate, mostly straight, sometimes oblique, exostome e narrowly triangular, shouldered, bordered, on the front surface with a zig-zag median line, cross-striolate below, papillose above, trabeculate at back; endostome smooth to finely papillose, with a high basal membrane, segments keeled, perforate, almost as long as the teeth, cilia often single, slightly shorter than the segments. Spores spherical, papillose. Calyptrae cucullate, naked, smooth.

• Discussion

  Discussion. Eulacophyllum is a monospecific genus widespread in tropical America. Its special features are the inclined, annulate capsules, with thick-walled exothecial cells and thin-walled annular cells. The leaves are often strongly asymmetric with a costa that projects as a spine at its apex. The small alar cells are mostly strongly unequally distributed on each side of the leaves.