Rauiella praelonga (Besch.) Wijk & Margad.

Authority

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

Family

Thuidiaceae

Scientific Name

Rauiella praelonga (Besch.) Wijk & Margad.

Description

Species Description - Plants small to medium-sized, in moderate, ± dense, dull, golden mats. Stems creeping, to ca. 6 cm long, mostly 2-3 cm, ± regularly 1-pinnate, not frondose, the branches to ca. 1 cm long, mostly shorter; in cross-section with 4-5 rows of small thick-walled cells surrounding larger thinner-walled cells, central strand small of small thin-walled cells; paraphyllia ± abundant on stems, sparse on branches (and then at the bases), mostly filamentous, uniseriate above and 2(-3)-seriate below, mostly unbranched, the cells oblate, papillose; pseudoparaphyllia foliose, of cells similar to those of the paraphyllia; axillary hairs usually with a single short brown basal cell and 2 elongate hyaline distal cells. Stem and branch leaves differentiated, stem leaves erect when dry, spreading to wide-spreading when moist, broadly ovate, 0.5-0.6 mm long, abruptly acuminate, concave, shortly and narrowly decurrent; margins serrulate in the acumen, otherwise crenulate throughout, plane in the acumen, mostly recurved below, rarely erect; costa single, ending near the base of the acumen, pellucid; cells quadrate to isodiametric, bulging on both surfaces, pluripapillose on both surfaces, with 3-5 papillae mostly around the periphery of the lumina, firm-walled, ca. 5-6 µm wide, becoming longer and smooth in the acumen; alar cells not differentiated. Branch leaves erect when dry, spreading to wide-spreading when moist, ovate, ca. 0.4 mm long, gradually broad-acuminate, slightly concave, shortly and narrowly decurrent; margins crenulate throughout, plane to irregularly recurved; costa single, ending ca. 4/5 the leaf length, pellucid below, obscure above by overlying laminal cells; cells quadrate to isodiametric, bulging on both surfaces, pluripapillose on both surfaces, with 4-6 papillae mostly around the periphery of the lumina, firm-walled, ca. 5-6 pm wide, not differentiated in the acumen but apical cell enlarged, pellucid, smooth, pointed; alar cells not differentiated. Asexual propagula none. Autoicous. [Sporophytes not known from the West Indies; description based on Mexican material.] Perichaetia conspicuous; leaves enlarged, erect, lanceolate, ca. 2.5 mm long, long-acuminate, plicate; margins subentire, plane; costa single, subpercurrent; cells rectangular to long-rectangular, smooth. Setae elongate, smooth, orange, 1-1.5 cm long; capsules horizontal, asymmetric and arcuate, short-cylindric, 1.5-2 mm long; exothecial cells ± isodiametric, thin- to firm-walled; annulus of 2-3 rows of thick-walled cells; operculum stoutly apiculate; exostome teeth yellow-brown, shouldered, bordered, on the front surface cross-striolate below, coarsely papillose above, trabeculate at back; endostome finely roughened throughout, with a high basal membrane, segments keeled, not or narrowly perforate, cilia in groups of 1-2. Spores spherical, finely papillose, ca. 17 µm diam. Calyptrae not seen.

Discussion

1. Rauiella praelonga (Besch.) Wijk & Margad., Taxon 11: 222. 1962; Pseudoleskea praelonga Schimp. ex Besch., Mém. Soc. Sci. Nat. Cherbourg 16: 233. 1872; Heterocladium mexicanum Schimp. ex Besch., Mém. Soc. Sci. Nat. Cherbourg 16: 233. 1872, nom. nud. in syn.; Rauia praelonga (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1005. 1907; Rauiella mexicana (Besch.) Wijk & Margad., Taxon 14: 197. 1965, comb. inval; Haplocladium praelongum (Besch.) H. A. Crum, Bryologist 72: 243. 1969; Bryohaplocladium praelongum (Besch.) H. A. Crum, Bryologist 87. 211. 1984. Plate 77, figures 1-10 Pseucloleskea subfilamentosa Kiaer ex Besch., Ann. Sci. Nat. Bot. VI, 10: 288. 1880; Rauia subfilamentosa (Besch.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1005. 1907; Rauiella subfilamentosa (Besch.) Wijk & Margad., Taxon 11: 222. 1962. Thuidium firmulum Müll. Hal., Hedwigia 36: 143. 1897; Rauia firmula (Müll. Hal.) Broth, in Engl. & Prantl, Nat. Pflanzenfam. 1(3): 1005. 1907; Rauiella firmula (Besch.) Wijk & Margad., Taxon 11: 222. 1962. Discussion. Within the West Indies this rare species is recognized by its bulging, pluripapillose leaf cells and by paraphyllia with oblate cells. It is closely related to the Central and northern South American R. lagoensis (Hampe) W. R. Buck, but that species differs in its unipapillose leaf cells. Rauiella praelonga differs from the North American R. scita (P. Beauv.) Reimers in the shorter acumen of the stem leaves and the nonpapillose apical cell of the branch leaves. Gier’s (1980: 264) report of R. scita from the West Indies has not been given credence.

Distribution

Range. Southwestern United States and Mexico to Argentina, eastern and southern Africa; known from two West Indian collections, one from Cuba (1929, Leon 13999, NY) and one from Hispaniola (Haiti, 1935, Thomas 29, NY); growing on dead branches and (?) rocks, probably in exposed habitats, at ca. 1500 m.

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