Leucodon julaceus (Hedw.) Sull.
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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
Leucodontaceae
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Scientific Name
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Description
Species Description - Plants rather slender to somewhat robust, in mostly dark-green, sometimes yellow-green, thin to dense mats. Primary stems creeping, slender, inconspicuous, with reduced, scale-like leaves, turning ca. 90° and becoming the secondary stem, the creeping stem continuing by a bud from near the base of the secondary stem, secondary stems erect, simple or less often sparsely branched, often curved when dry, to ca. 2 cm long, julaceus, sometimes becoming attenuate; in cross-section with 1-3 rows of small thick-walled cells surrounding larger firm-walled cells, central strand none; paraphyllia none; pseudoparaphyllia foliose; axillary hairs with 2 short brown basal cells and 2 elongate hyaline distal cells. Secondary stem leaves dense, appressed when dry, not secund, rapidly wide-spreading when moist, oblong-ovate, 0.9-1.3 mm long, abruptly short-acuminate, concave, not or scarcely plicate when dry, broadly decurrent; margins serrulate above, entire below, mostly plane throughout, sometimes narrowly recurved below or erect at base of acumen; costa none; cells oval to rhomboidal, 24:1, smooth or sometimes prorulose above, thick-walled, ± porose, becoming ± linear in the acumen and toward the insertion; alar cells subquadrate to oblate, collenchymatous, extending up the margins to ca. 1/2 the leaf length. Asexual propagula none. Dioicous but often fertile. Perichaetial leaves erect, convolute, oblong-lanceolate, to 3.5 mm long, gradually acuminate; margins entire, plane; costa none; cells long-rectangular to linear, smooth, firm-walled, porose, becoming shorter and thinner-walled toward the insertion. Setae ± elongate, smooth, yellow-brown, 2.5-4(-8) mm long, twisted when dry; capsules short-exserted, erect and symmetric, oval-cylindric, 1.1-1.5 mm long, yellow-brown, narrowed to the reddish mouth; exothecial cells short-rectangular, firm-walled, becoming oblate in 4-6 rows at the mouth; annulus none; operculum obliquely rostrate, ca. 0.8 mm long; peristome double, inserted below the mouth, exostome teeth pale, without a prostome or rarely with scattered prostomial fragments adhering to the teeth, on the front surface with a ± straight median line, coarsely papillose, not or scarcely trabeculate at back; endostome only a low, coarsely papillose basal membrane, scarcely higher than the mouth of the urn. Spores spherical, densely papillose, 31-43 µm diam. Calyptrae cucullate, large, tardily deciduous and ± clasping the seta below the urn, naked, smooth.
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Discussion
1. Leucodon julaceus (Hedw.) Sulk, Musci Allegh. 87. 1845 [1846]; Pterigynandrum julaceum Hedw., Sp. Musc. Frond. 81. 1801; Pterogonium julaceum (Hedw.) Schwagr., Sp. Muse. Frond. Suppl. 1(1): 100. 1811; Hypnum julaceum (Hedw.) L. ex Schleich., Cat. Pl. Helv. ed. 4, 41. 1821, hom, illeg., non (Schrad. ex P. Gaertn., B. Mey. & Scherb.) F. Weber & D. Mohr, Index Mus. Pl. Crypt. 3. 1803 [= Anomobryum julaceum (P. Gaertn., B. Mey. & Scherb.) Schimp.], nec (Schwagr.) Vill. ex Schwagr., Sp. Muse. Frond. Suppl. 1(2): 216. 1816, hom, illeg. [= Myurella julacea (Schwagr.) Schimp.], nec Broth., Bih. Kongl. Svenska Vetensk.-Akad. Handl. 21, Afd. 3(3): 63. 1895, hom. illeg. [= Platyhypnidium brotheri (Paris) Wijk & Margad.]; Neck-era pseudalopecura Müll. Hal., Syn. Muse. Frond. 2: 92. 1850, non Neckera julacea Hook, ex Schwagr., Sp. Musc. Frond. Suppl. 3(1): 245. 1828 [= Erxthrodontium julaceum (Schwagr.) Paris]. Plate 68, figures 1-7 Discussion. Leucodon julaceus is characterized by oblong-ovate, abruptly short-acuminate, ecostate leaves with short median cells. The secondary stems are usually simple and curved when dry. The habitat, on trees near streams, should prevent any confusion with saxicolous Hedwigiaceae.
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Distribution
Range. Eastern North America, Mexico; Hispaniola (Dominican Republic, La Vega Prov., Salto de Constanza, Buck 7896, Norris 1255, NY); growing on tree trunks, often near streams, at ca. 1200 m.
North America| Mexico North America| Dominican Republic South America|