Monographs Details: Schwetschkeopsis
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants small, in mostly ± lustrous, green to golden, soft, dense, flat, often extensive mats. Stems creeping, freely and irregularly branched, often attenuate, terete-foliate or ± complanate; in cross-section with small thick-walled cells surrounding larger thinner-walled cells, central strand none; rhizoids tufted along undersides of stems; pseudoparaphyllia foliose; axillary hairs with 1-2 short brown basal cells and a single somewhat elongate hyaline distal cell. Stem and branch leaves similar, crowded, appressed when dry, erect to erect-spreading when moist, sometimes ± complanate, ovate-lanceolate, acuminate, concave, not or shortly decurrent; margins serrulate throughout except at alar region, plane; costa none or rarely short and apparently single; cells long-hexagonal, prorulose, firm-walled; alar cells well differentiated, subquadrate. Asexual propagula none. Phyllodioicous. Perichaetial leaves sheathing, lanceolate to long-triangular, gradually acuminate; margins serrulate above, subentire below, plane; costa none; cells smooth or obscurely prorulose, short-linear, thick-walled and porose in the acumen, becoming broader, short and nonporose below, quadrate all across the insertion. Setae elongate, smooth, reddish, flexuose; capsules erect to suberect, symmetric, cylindric; exothecial cells subquadrate to short-rectangular, thin-walled, not collenchymatous; annulus not differentiated; operculum obliquely conic-rostrate; columella cylindric, not expanded at apex, ending slightly below midurn; peristome double, attached at the mouth, exostome teeth narrowly triangular, shouldered, bordered, on the front surface with a zig-zag median line, cross-striolate below, papillose above, trabeculate at back; endostome with a moderately high basal membrane, segments keeled, perforate, ca. as long as the teeth, cilia none. Spores spherical, papillose. Calyptrae cucullate, naked, smooth.
Discussion:Discussion. Schwetschkeopsis is characterized by densely matted plants with ecostate leaves and relatively short, prorulose laminal cells. It differs from both Helicodontium and Austinia by the ecostate leaves and prorulose leaf cells. We have but a single species in our area. Capsules of Schwetschkeopsis, rarely produced outside of Asia, are erect (to suberect) with a hypnoid peristome that lacks cilia. The genus is one of eastern Asian-eastern North American disjunction. Since the genus occurs primarily at low elevations, its distribution is probably due to ancient dispersal and not modern occurrence.