Hamatocaulis vernicosus (Mitt.) Hedenäs

Authority

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

Family

Campyliaceae

Scientific Name

Hamatocaulis vernicosus (Mitt.) Hedenäs

Description

Species Description - Plants medium-sized to robust, in ± stiff, ± lustrous, green to brown, often reddish-tinged tufts. Stems erect-ascending, to ca. 15 cm tall but often much shorter, ± pinnately branched ± in a single plane, the stem apex and to a lesser degree the branch apices hooked-foliate; in cross-section with 1-2 rows of small thick-walled cells surrounding larger thinner-walled cells, central strand none; paraphyllia absent; pseudoparaphyllia broadly foliose; axillary hairs with 1-2 short brown basal cells and (2-)3-4(-6) elongate hyaline distal cells. Stem and branch leaves similar, crowded, with a ± erect base and rather abruptly curved above midleaf, ovate-lanceolate to ± oblong-ovate, the stem leaves 1.5-2 mm long, those of the branches smaller, gradually acuminate, concave, slightly plicate sometimes smooth in branch leaves), not or hardly decurrent; margins entire or finely toothed at extreme apex but otherwise entire, plane; costa single, ending near or somewhat above midleaf; cells linear, ± flexuose, smooth, thin-walled and not porose to firm-walled and porose, becoming wider, thicker-walled and strongly porose toward the insertion; alar cells not differentiated. Asexual propagula none. Dioicous. [Sporophytes not known from the West Indies; description based on North American material.] Perichaetia enlarged, conspicuous; leaves erect, sheathing, ovate-lanceolate, to ca. 3.5 mm long, acuminate, plicate; margins mostly entire, plane to slightly recurved; costa single, ending above midleaf; cells linear, smooth, firm- to thick-walled, ± porose, becoming shorter, broader, and laxer toward the insertion; alar cells not differentiated. Setae elongate, smooth, reddish, 3.5-6.5 cm long, twisted; capsules inclined, arcuate, asymmetric, cylindric, 2-3.5 mm long; exothecial cells subquadrate to short-rectangular, firm-walled; annulus of 2-3 rows of cells, deciduous; operculum conic-apiculate; exostome teeth yellow-brown, shouldered, strongly bordered, on the front surface finely papillose-reticulate below, coarsely papillose above, trabeculate at back; endostome with a high basal membrane, segments keeled, not or narrowly perforate, cilia in groups of 2-3, well developed, nodulose. Spores spherical, nearly smooth to finely papillose, 12-22 µm diam. Calyptrae cucullate, naked, smooth.

Discussion

1. Hamatocaulis vernicosus (Mitt.) Hedenãs, Lindbergia 15: 27. 1989; Hypnum vernicosum Lindb. in Hartm., Handb. Skand. Fl. ed. 8, 342. 1861, hom. illeg., non Hampe, Linnaea 10: 406. 1836; Stereodon vernicosus Mitt., J. Linn. Soc., Bot. 8: 43. 1864; Hypnum aduncum var. vernicosum (Mitt.) Molendo, Ber. Naturhist. Vereins Augsburg 18: 100. 1865; Amblystegium vernicosum (Mitt.) Lindb., Musci Scand. 33. 1879; Hypnum lycopodioides var. vernicosum (Mitt.) Sanio, Bot. Centralbl. 4(Beil. 2): 23. 1880; Harpidium vernicosum (Mitt.) C. E. O. Jensen, Meddel. Grønland 3: 326. 1887; Amblystegium lycopodioides var. vernicosum (Mitt.) Lindb. & Arnell, Kongl. Svenska Vetenskapsakad. Handl. 23(10): 121. 1890; Hypnum revolveos subsp. vernicosum (Mitt.) Kindb., Canad. Rec. Sci. 6: 74. 1894; Hypnum cossonii subsp. vernicosum (Mitt.) Kindb., Eur. N. Amer. Bryin. 1: 129. 1896 [1897], nom. illeg.; Drepanocladus vernicosus (Mitt.) Warnst., Beih. Bot. Centralbl. 13: 402. 1903; Limprichtia vernicosa (Mitt.) Loeske, Hedwigia 46: 310. 1907; Scorpidium vernicosum (Mitt.) Tuom., Ann. Bot. Fenn. 10: 216. 1973. Plate 86, figures 8-15 Discussion. Hamatocaulis vernicosus is characterized by ± erect stems lacking a central strand, leaves abruptly curved above midleaf, and little alar development. When this species was first reported for the West Indies (Hedenãs, 1989a), it was speculated that its presence was best explained by a bird-dispersed event. A more plausible explanation is that during maximum glaciation the range of the species was much further south and thus easily dispersed to an adjacent area of compatible habitat. Subsequent climatic changes have left it far disjunct. Thus, H. vernicosus in the Dominican Republic might best be explained as relictual from a past vicariance event (cf. Buck, 1990).

Distribution

Range. Canada (but not high Arctic), northern United States, Colombia, Venezuela, northern to central Europe, eastern Asia (Vladivostok), reported from Japan; Hispaniola (Dominican Republic); growing on soil, in an area of hardwood shrubs along a stream in a pine forest, at 1950 m; known from a single collection (Ekman 13594, S!) made in 1929.

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