Monographs Details: Acroporium
Authority: Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
Description:Genus Description - Plants slender to fairly robust, in mostly lustrous, ± stiff, yellow-green to golden, often dense, extensive mats. Stems creeping to pendent, freely but irregularly branched, the branches usually ascending, densely foliate, characteristically cuspidate; in cross-section with small thick-walled colored cells surrounding larger mostly firm-walled cells, central strand absent; pseudoparaphyllia foliose; axillary hairs with a single short-rectangular brown basal cell and 1 to several elongate hyaline distal cells. Stem and branch leaves similar, erect- to wide-spreading, lanceolate to ovate, acuminate, concave to tubulose; margins entire to serrulate above, subentire below, mostly plane or incurved above; costa short and double or absent; cells linear, sometimes flexuose, smooth or rarely unipapillose, thick-walled, often porose; alar cells greatly enlarged and inflated in well-differentiated basal groups, colored, mostly ± oblong, usually curved toward the insertion. Asexual propagula rare. Mostly autoicous, rarely synoicous or dioicous. Perichaetia inconspicuous; leaves erect, lanceolate to ovate, acuminate; margins serrate to serrulate, plane; costa mostly none; cells linear, smooth, thick-walled, porose; alar cells not differentiated. Setae elongate, slender, roughened above or smooth throughout, reddish; capsules erect to pendent, ± asymmetric, short-cylindric; exothecial cells mostly subquadrate, strongly collenchymatous; annulus not differentiated; operculum obliquely and slenderly long-rostrate; peristome double, exostome teeth triangular, shouldered, bordered, on the front surface with a median furrow, cross-striolate below, coarsely papillose above, trabeculate at back; endostome with a high basal membrane, segments mostly broad, keeled, perforate, almost as long as the teeth, cilia mostly single. Spores spherical, finely papillose. Calyptrae cucullate, naked, smooth or almost so.
Discussion:Acroporium Mitt., J. Linn. Soc., Bot. 10: 182. 1868.
Pungentella Müll. Hal., Flora 82: 470. 1896, nom. nud., non Nuovo Giorn. Bot. Ital. II, 4: 152. 1897 [= Sematophyllum Mitt.J. Schraderobryum M. Fleisch., Musci Buitenzorg 4: 1177. 1923.
Discussion. Acroporium is characterized by mostly golden plants with cuspidate branch apices. The leaves are concave with greatly enlarged, colored, obliquely oriented alar cells. These gametophytic characters coupled with furrowed exostome teeth, but an otherwise hypnoid peristome, give the genus meaning.
Acroporium is rather poorly represented in the New World, but is much more diverse in the Old World tropics. The insular Malesian species have been treated by Tan (1994).