Monographs Details: Phyllogonium
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants medium-sized to robust, in lustrous, green to golden to bronze, pendent, often extensive, epiphytic colonies. Primary stems creeping, tightly attached to the substrate, with reduced, scale-like leaves, turning ca. 90° and becoming the pendent secondary stem, the creeping stem continuing by a bud from near the base of the secondary stem, secondary stems irregularly branched, pendent, strongly complanate-foliate; in cross-section with 3-4 rows of small thick-walled cells surrounding larger thinner-walled cells, central strand none; paraphyllia none; pseudoparaphyllia broadly foliose; axillary hairs with 1-3 short brown basal cells and 2-5 elongate hyaline distal cells. Secondary stem and branch leaves not differentiated, little altered when dry, strongly complanate, erect-spreading to spreading, oblong to oblong-ovate (in profile), truncate or recurved- or retuse-cuspidate, conduplicate-cucullate, auriculate; margins entire or with a few small teeth at extreme apex, incurved above or almost throughout; costa short and double or absent; cells linear, subflexuose, smooth, firm- to thick-walled, porose, shorter in the extreme apex, becoming somewhat shorter toward the yellowed insertion; alar cells usually strongly colored, short-rectangular, thick-walled, porose, in small, ± excavate groups. Asexual propagula none. Dioicous. Perichaetia inconspicuous or conspicuous; leaves ± convolute, broadly oblong-ovate, abruptly acuminate, sometimes retuse, concave but not conduplicate; margins subentire to serrulate-crenulate, plane; costa short and double or absent; cells linear, smooth, thick-walled, porose. Setae short, smooth, reddish, arising from a hairy vaginula; capsules immersed to short-exserted, erect and symmetric, short-cylindric to urceolate; exothecial cells quadrate to rectangular, firm- to thick-walled; annulus differentiated, fragmenting; operculum obliquely conic-rostrate; peristome single (endostome absent) or double, shallowly inserted below the mouth, exostome teeth pale, incurved when dry, erect when moist, smooth or finely roughened, sometimes perforate, sometimes with prostome, not trabeculate at back; endostome, when present, reduced to a low basal membrane, with or without rudimentary segments. Spores spherical, finely roughened. Calyptrae cucullate or mitrate, naked or hairy, roughened.
Discussion:Discussion. Phyllogonium is immediately recognizable by its typically golden color and pendent habit, and the conduplicate-cucullate, strongly complanate leaves with linear, porose cells. There are only three species in the genus. Lin (1983) recently monographed the genus in detail and reported all three species from the West Indies. However, one of these, P viscosum (P. Beauv.) Mitt., is tentatively excluded here. Lin reported it from a single old collection without data from Jamaica and a specimen from Puerto Rico. Since both of these islands are relatively well collected and this conspicuous moss has not been found, it is suspected that the two collections may not have actually come from the Antilles. Nevertheless, the species is discussed and illustrated, but not described, below.