Isopterygium Mitt.
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Authority
Buck, William R. 2003. Guide to the plants of central french Guiana. Part 3. Mosses. Mem. New York Bot. Gard. 76: 1-167.
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Family
Hypnaceae
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Scientific Name
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Description
Genus Description - Plants small to medium- sized, in often lustrous, mostly soft, pale to yellowish green, sometimes brown- tinged, thin to dense mats; stems creeping, almost simple or irregularly but freely branched, often obscurely complanate- foliate, in cross- section with a sclerodermis, almost always with filamentous pseudoparaphyllia. Stem and branch leaves similar, crowded to lax, usually complanate, erect to erect - spreading to wide spreading, symmetric or asymmetric, lanceolate to ovate, acute to acuminate, mostly gradually so, concave of flate, nondecurrent or short - decurrent by 1-2 cells; margines entire to serrulate above, subentire to entire below, plane to erect or incurved, often recurved below; costa short and double or absent; cells linear, often flexuose, smooth, thin- to firm - walled, not porose, no becoming shorter in the acumen, becoming shorter, ± rectangular and sometimes porose toward the insertion; alar cells differentiated, few, quadrate to short- rectangular, in extreme angles, not reacning in the costa. Asexual propagula rare. Mostly autoicous. setae elongate, smooth, reddish, twisted, straight or curved just below the urn; capsules erect to inclined or pendent, straight to arcuate, cylindric to short - cylindric, constricted below the mouth when dry; peristome double, exostome teeth on the front surface cross- striolate below, coarsely papillose above; endostome with a low to hogh basal membrane, segments narrow to broad, keeled, not or narrowly perforate, shorter than or about as long as the teethm cilia absent or in groups of 1-3, usually papillose. Calyptrae cucullate, naked smooth. Isopterygium is often a difficult genus to recognize. The plants are usually ± complanate and often pale green, presumably adapted to low light intensities. The leaves are often somewhat asymmetric. The filamentous pseudoparaphyllia are often the best way to be sure of identification. Ireland (1991, 1992) has published two accounts of Isopterygium in Latin America.