Hypnum polypterum (Mitt.) Broth.
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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
Hypnaceae
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Scientific Name
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Description
Species Description - Plants medium-sized, in often lustrous, stiff, mostly golden, sometimes green or brownish green, often extensive, dense mats. Stems creeping or ascending, to ca. 8 cm long, often regularly and densely pinnate, the branches often straight, to ca. 1 cm long; in cross-section without a hyalodermis, with 3-5 rows of small thick-walled colored cells surrounding larger thinner-walled cells, central strand small, of small thin-walled cells; pseudoparaphyllia foliose; axillary hairs with a single short brown basal cell and 3(-4) relatively short hyaline distal cells. Branch and stem leaves somewhat differentiated, stem leaves falcate-secund, oblong-ovate-lanceolate to ovate, 2-2.5 mm long, gradually short-acuminate, concave, plicate, subcordate at base; margins serrulate throughout, plane to erect, occasionally narrowly incurved; costa double, relatively strong, extending to ca. of the leaf length; cells linear, subflexuose, 15-30:1, smooth, thick-walled, slightly and not conspicuously porose, becoming shorter and more porose toward the insertion; alar cells differentiated in extreme basal angles, often in excavate areas, subquadrate to short-rectangular, very thick-walled, porose, sometimes colored. Branch leaves falcate-secund, lanceolate to ovate-lanceolate, 1-1.5 mm long, gradually short-acuminate, concave, often plicate, somewhat curved to the insertion but not cordate; margins serrulate throughout, plane to erect, occasionally narrowly incurved; costa double, relatively strong, extending to ca. 1/4 the leaf length; cells linear, subflexuose, 15-30:1, smooth, thick-walled, slightly and not conspicuously porose, becoming shorter and more porose toward the insertion; alar cells differentiated in extreme basal angles, often in excavate areas, subquadrate to short-rectangular, very thick-walled, porose, sometimes colored. Asexual propagula none. Dioicous. Perichaetia conspicuous; outer leaves secund, the inner ones erect, oblong-lanceolate, 3.5-4 mm long, abruptly long-subulate; margins coarsely notched at shoulders, otherwise entire, plane; costa none; cells linear, straight, smooth, thick-walled, porose, becoming broader, thicker-walled and more porose toward the insertion; alar cells scantily differentiated in extreme angles, short-rectangular, thick-walled, porose. Setae elongate, smooth, reddish, 3-4.5 cm long; capsules inclined, symmetric, long-cylindric, 2.5-4 mm long; exothecial cells quadrate to rectangular, firm-walled, weakly collenchymatous, stomata mixed cryptopore and phaneropore; annulus of 1-3 rows of small subquadrate thick-walled cells, tardily deciduous; operculum short conic-rostrate, straight; exostome teeth shouldered, bordered, on the front surface cross-striolate below, the striolae overlaid with minute spiculae, papillose above, trabeculate at back; endostome with a medium-high basal membrane, segments spiculose, narrow, keeled, not or narrowly perforate, ca. as long as or longer than the teeth, cilia rudimentary. Spores mostly ovoid to oblong, occasionally spherical, finely and densely papillose, 27-50 µm long. Calyptrae cucullate, naked, smooth.
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Discussion
2. Hypnum polypterum (Mitt.) Broth, in Engl., Nat. Pflanzenfam., ed. 2, 11: 454. 1925; Ectropothecium polypterum Mitt., J. Linn. Soc., Bot. 12: 514. 1869; Stereodon polypterus (Mitt.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1071. 1908; Caribaeohypnum polypterum (Mitt.) Ando & Higuchi, Cryptog. Bryol. Lichénol. 5: 9. 1984. Plate 118, figures 8-13 Cupressina arcuatipes Müll. Hal., Bull. Herb. Boissier 5: 566. 1897. Ptilium orthothecium Thér., Rev. Bryol. Lichénol. 14: 21. 1944. Discussion. Hypnum polypterum is an attractive moss, occurring rather commonly at higher elevations in Jamaica and Hispaniola. All collections seen from Cuba were collected in the Sierra Maestra and all but one from Pico Turquino. The species is likely to be confused only with H. amabile. However, H. polypterum is characterized by short-acuminate leaves that are serrulate to the base, with a strong, double costa, and small, thick-walled alar cells. There might be some superficial resemblance to Ectropothecium but our local species are much smaller and have a single inflated cell in each basal leaf angle. West Indian collections range greatly in size, apparently a result of environmental parameters, especially light, and to a lesser extent humidity. Consequently I do not have much faith in the var. robustum E. B. Bartram, which occurs throughout the range of the species. Ando and Higuchi (1984) suggested that Hypnum polypterum is not closely related to other Hypnum species and deserves generic status as Caribaeohypnum. They were much impressed by the plicate leaves and reduced peristome, including the spiculose deposition on the exostomial cross-striolae. However, in aspect it is very similar to H. amabile and gametophytically differs from that species mainly in the alar cells—hardly a generic difference, in my opinion.
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Distribution
Range. Mexico to Panama, northern Andean South America; Cuba (Sierra Maestra), Jamaica, Hispaniola (Haiti and Dominican Republic), Guadeloupe; mostly growing on soil, humus, or tree bases and branches, in montane forests, at (1000-)2000-3200 m.
Mexico North America| Central America| Venezuela South America| Colombia South America| Ecuador South America| Peru South America| Bolivia South America| Chile South America| Argentina South America| Cuba South America| Jamaica South America| Haiti South America| Dominican Republic South America| Guadeloupe South America|