Isopterygium tenerifolium Mitt.

  • Authority

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

  • Family

    Hypnaceae

  • Scientific Name

    Isopterygium tenerifolium Mitt.

  • Description

    Species Description - Plants medium-sized, in lustrous, mostly soft, dark-green when alive, becoming yellow-green, thin mats. Stems creeping, to ca. 4 cm long, flaccid, irregularly but freely branched, the branches simple, complanate-foliate; in cross-section with 1-3 rows of relatively large firm-walled cells surrounding somewhat larger thinner-walled cells, central strand absent, stem becoming hollow with age; pseudoparaphyllia filamentous; axillary hairs (few seen) with a single relatively long brown basal cell and 1-2 elongate hyaline distal cells. Stem and branch leaves similar, crowded, complanate, wide-spreading to squarrose, often curved and asymmetric, although rarely straight and ± symmetric, ovate-lanceolate to ovate, 1.1-1.5 mm long, gradually acuminate, ± concave; margins minutely serrulate throughout, mostly narrowly erect ± throughout, rarely plane; costa short and double and indistinct or absent; cells linear, subflexuose, smooth, thin-walled, not porose, somewhat shorter in the acumen, becoming shorter in 1-2 rows across the insertion; alar cells few in extreme basal angles, not reaching the costa, 2-4, in 1-2 rows, extending up the margins by 1-2 cells, subquadrate to short-rectangular. Asexual propagula not seen. Autoicous. Perichaetial leaves erect, oblong-lanceolate, 1.6-1.9 mm long, abruptly tapered at ca. midleaf, then gradually acuminate; margins serrulate throughout, plane; costa none; cells linear, smooth, thick-walled, porose, becoming shorter and rectangular toward the insertion; alar cells not differentiated. Setae elongate, smooth, reddish, (2-)2.5-3(-4) cm long, twisted, curved just below the urn; capsules horizontal to pendent, arcuate, asymmetric, cylindric, 1-1.5 mm long, constricted below the mouth dry or moist; exothecial cells quadrate to rectangular, firm-walled, the walls ± sinuose, ± collenchymatous; annulus not differentiated; operculum short conic-rostrate, often oblique; exostome teeth shouldered, bordered, on the front surface cross-striolate below, coarsely papillose above, trabeculate at back; endostome with a high, smooth basal membrane, segments smooth, broad, keeled, mostly not but occasionally narrowly perforate, ca. as long as the teeth, cilia papillose, in groups of 2-3, shorter than the segments. Spores spherical, finely papillose, 8.5-12 µm diam. Calyptrae cucullate, naked, smooth.

  • Discussion

    4. Isopterygium tenerifolium Mitt., J. Linn. Soc., Bot. 12: 499. 1869. Plate 125, figures 1-8 Ectropothecium longisetum Schimp. ex Besch., Ann. Sci. Nat. Bot. VI, 3: 258. 1876; Isopterygium longisetum (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1082. 1908, hom. illeg., non Broth., Bih. Kongl. Svenska Vetensk.-Akad. Handl. 21 Afd. 3(3): 55. 1895 [= Isoptengium tenerifolium Mitt.]; Isopterygium altisetum H. A. Crum & Steere, Bryologist 59: 254. 1956. Hxpnum husnotii Schimp. ex Besch., Ann. Sci. Nat. Bot. VI, 3: 262. 1876; Campylium husnotii (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1044. 1908. Discussion. Isopterygium tenerifolium is characterized by usually curved, asymmetric leaves with erect margins. The setae are much longer than in our other species and the endostomial cilia are in groups of 2-3, rather than occurring singly or not at all. The species has mostly gone under the name I. altisetum, a nomen novum for I. longisetum Besch. However, an examination of the northern South American species indicates that I. tenerifolium is the same as the West Indian material, thereby replacing I. altisetum. One certainly gets the feeling that, even over time, bryologists have had trouble with Isopterygium: within our flora are I. tenerum, I. tenerifolium, and I. subtenerrimum (a synonym of I. subbrevisetum).

  • Distribution

    Range. United States (Mississippi), Mexico, Honduras, Costa Rica, Panama, Venezuela, Colombia, Ecuador, Bolivia, northeastern Argentina, Paraguay, eastern Brazil, Guyana, Surinam; Cuba, Jamaica, Hispaniola (Dominican Republic), Guadeloupe, Dominica, Martinique; mostly growing on rotten wood, in open, moist forests, at 200-2500 m.

    United States of America North America| Mexico North America| Honduras Central America| Costa Rica South America| Panama Central America| Venezuela South America| Colombia South America| Ecuador South America| Bolivia South America| Argentina South America| Paraguay South America| Brazil South America| Guyana South America| Suriname South America| Cuba South America| Jamaica South America| Dominican Republic South America| Guadeloupe South America| Dominica South America| Martinique South America|