Rigodium toxarion (Schwägr.) A.Jaeger
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Authority
Buck, William R. 1998. Pleurocarpous mosses of the West Indies. Mem. New York Bot. Gard. 82: 1-400.
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Family
Lembophyllaceae
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Scientific Name
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Description
Species Description - Plants medium-sized, the stipes to 2.5 cm long, the stems to 3.7(-12) cm long, in wiry, loose, green to golden mats. Stems erect to arcuate, irregularly pinnately branched from a differentiated stipe, the higher levels of branches progressively smaller; in cross-section with 5-7 rows of small thick-walled cells surrounding larger thin-walled cells, central strand of very small thin-walled cells; paraphyllia none; pseudoparaphyllia foliose; axillary hairs with a single short brown basal cell and 1(-2) elongate reddish distal cells. Stem, stipe and branch leaves differentiated, stipe leaves wide-spreading to squarrose, ovate to broadly ovate, with a wide insertion, 0.5-0.9 mm long, acute at base of stipe, long-acuminate above, concave, somewhat decurrent; margins serrulate throughout, more strongly so above, plane; costa none; cells rounded long-rectangular, 5-10:1, smooth, thick-walled, not porose; alar cells somewhat and gradually differentiated in extreme angles, quadrate to subquadrate, concolorous. Stem leaves (above first branch) erect- to wide-spreading, the apices spreading to squarrose-recurved, ovate to broadly ovate, with a wide insertion, 0.8-1.1 mm long, abruptly long-acuminate, slightly concave, somewhat decurrent; margins serrulate throughout or rarely subentire, plane or narrowly incurved below; costa single, ending in the acumen well below the apex; cells oval to rounded short-rectangular, 2-5:1, smooth, thick-walled, not porose; alar cells gradually differentiated in basal angles and extending up the margins, often in concave areas near the insertion, quadrate to short-rectangular. Branch leaves erect-spreading, scarcely altered when moist, lanceolate to lanceolate-ovate, the ultimate ones shorter and narrower, 0.25-0.55 mm long, gradually acuminate, somewhat concave, somewhat decurrent; margins irregularly serrulate throughout, more strongly so above, plane; costa single, ending in the acumen well below the apex; cells rounded-isodiametric to oval, 1-3:1, smooth, thick-walled, not porose; alar cells not differentiated. Asexual propagula none. Dioicous. [Sporophytes not known from the West Indies; description based on material from Central America.] Perichaetia large, conspicuous; outer leaves squarrose-recurved, inner ones erect, oblong-lanceolate, 2-2.9 mm long, gradually long-acuminate; margins serrulate above, subentire below, plane; costa none; cells linear to linear-flexuose and thick-walled above, rectangular and thinner-walled below, smooth. Setae elongate, smooth, reddish, ca. 1.5 cm long, somewhat flexuose, curved above; capsules suberect to horizontal, symmetric, short-cylindric, not constricted at the mouth, brownish, 1.2-1.5 mm long; exothecial cells subquadrate to short-rectangular, firm-walled, not collenchymatous, stomata immersed, long-pored; annulus of 2-3 rows of cells, the top one very thick-walled, enlarged; operculum conic short-rostrate, straight, ca. 0.75 mm long; exostome teeth shouldered, scarcely bordered, on the front surface cross-striolate below, papillose above, trabeculate at back; endostome papillose, with a high basal membrane, segments keeled, gaping, cilia in groups of 1-2, nodulose. Spores spherical, finely papillose, 14-19 µm diam. Calyptrae cucullate, naked, smooth or finely roughened above.
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Discussion
1. Rigodium toxarion (Schwagr.) A. Jaeger, Ber. Thätigk. St. Gallischen Naturwiss. Ges. 1876-77: 244. 1878; Hypnum toxarion Schwägr., Sp. Musc. Frond. Suppl. 1(2): 283. 1816. Plate 71, figures 1-9 Rigodium gracile Renauld & Cardot, Bull. Soc. Roy. Bot. Belgique 32(1): 197. 1893 [1894]. Discussion. There is little else that can be confused with Rigodium toxarion. It might be mistaken for a Thuidium on casual observation but the smooth leaf cells and lack of paraphyllia, as well as a different branching pattern, preclude consideration of that genus. There might be some confusion with stipitate-frondose species of Porotrichum, but in Rigodium toxarion the laminal cells are much shorter.
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Distribution
Range. Mexico to Panama, Colombia and Venezuela, south through the Andes into central Chile, southeastern Brazil and adjacent Uruguay, east-central Africa, Madagascar; Hispaniola (Haiti and Dominican Republic); growing on rocks, lower tree trunks, and soil, in humid and cloud hardwood forests, at 1650-2350 m.
Mexico North America| Central America| Colombia South America| Venezuela South America| Ecuador South America| Peru South America| Bolivia South America| Chile South America| Brazil South America| Uruguay South America| Africa| Madagascar Africa| Haiti South America| Dominican Republic South America|