31. BELLIBARBULA Plate 40.

Bellibarbula Chen, Type: Bellibarbula kurziana Chen, Hedwigia 80: 223, 1941, India, “Sikkim, Phalloot Top,” Kurz 2026, BM, lectotyp. nov.; NY, isotype.

Plants forming a low turf, green to red-orange above, blackish red-brown below. Stems branching occasionally, to 3.0 cm in length, transverse section rounded-pentagonal, central strand present, sclerodermis thick, hyalodermis absent; axillary hairs short, 3–4 cells in length, basal 1(–2) cells yellow; sparsely radiculose. Leaves appressed, incurved when dry, weakly spreading when moist, short-lanceolate, often concave at midleaf, ca. 0.7–1.5(–2.0) mm in length, upper lamina broadly and deeply channeled along costa, margins strongly recurved in lower 3/4 or to near apex, entire; apex rather narrowly blunt to acute and sometimes apiculate; base ovate; costa ending 2–4 cells below apex or percurrent, sinuose above midleaf, superficial cells elongate or quadrate near apex ventrally, elongate dorsally, ca. 3–4 rows of cells across costa ventrally at midleaf, costal transverse section semicircular or circular, two stereid bands present, epidermis present on both sides of costa, guide cells 4 in 1 layer, hydroid strand absent; upper laminal cells rounded-quadrate to short-rectangular, occasionally transversely elongated in patches, ca. 10–13 µm in width, 1–2:1(–2), walls thin to incrassate, lumens angular to oval or elliptical, superficially flat to weakly convex; papillae small, simple to bifid, solid or hollow, 4–6 per lumen; basal cells not differentiated or weakly developed medially, quadrate to rectangular, not wider than upper cells, 1(–4):1, walls thin- to thick-walled. Dioicous. Perichaetia terminal, highly differentiated, inner leaves long-rectangular, apiculate, to 2.0 mm in length, convolute-sheathing, cells long-rhomboidal to near apex. Perigonia terminal, gemmate, often in series from subterminal innovations. Seta ca. 4–6 mm in length, 1 per perichaetium, reddish brown, twisted clockwise; theca 0.8–1.4 mm in length, reddish brown, cylindrical, exothecial cells thin-walled, rhomboidal, stomates numerous at base of theca, annulus of highly vesiculose cells, revoluble; peristome absent. Operculum short-conic, ca. 0.4–0.5 mm in length, cells straight. Calyptra cucullate, smooth, ca. 2.0 mm in length. Spores 15–18 µm in diameter, brownish, lightly papillose. Laminal KOH color reaction red.

Found on rock in montane situations in the Himalayas of India, China (Yunnan), the Appalachians of the U.S.A., and mountain ranges in Mexico.

Bellibarbula was proposed by Chen (1941) for two species distinguished from other Barbuleae by strongly convolute-sheathing perichaetial leaves (Pl. 40, f. 10, 11, 16), peristome absent, ovate-lanceolate leaves, papillose upper laminal cells (Pl. 40, f. 9) and little-differentiated leaf bases (Pl. 40, f. 7). The genus proves to be similar to Bryoerythrophyllum in the red coloration and small, bifid laminal papillae. Bryoerythrophyllum shows a tendency towards Bellibarbula in that some of its species likewise have an eperistomate capsule with short-conic operculum. Bellibarbula is easily distinguished, however, by the costa usually sinuose above (Pl. 40, f. 4, 5, 13, 14), rather concave upper lamina (at least in collections with incrassate cell walls), and the highly differentiated, convolute-sheathing inner perichaetial leaves with long, rhomboidal cells extending to the apiculate apex. Didymodon nigrescens and related species are similar to Bellibarbula in the red coloration, incrassate upper laminal cells, generally elongate ventral costal cells and short basal cells, but differ in their very thin costae and lack of papillae or papillae low and massive.

Judging from study of a range of specimens and the types at BM and PC, the two species of Bellibarbula are only weakly distinguishable by the features mentioned in Chen's (1941) key and as discussed (in Chinese) by Chen (1963). The type of B. kurziana includes some plants with much the same morphology as the second species. Bellibarbula obtusicuspis of China (type at PC!) is clearly the same as what has been known as Bryoerythrophyllum recurvum, and a new combination is necessary along with extension of known morphological variation (description by Zander 1978g) and geographic range of the species (United States and Mexico).

Number of accepted species: 2.

Species examined: B. kurziana (BM, NY), B. recurva (BUF, DUKE, MICH, PC, TENN).

New heterotypic synonymy: Bellibarbula obtusicuspis (Besch.) Chen = Bellibarbula recurva (Griff.) Zand.

New combinations: Bellibarbula recurva (Griff.) Zand., comb. nov. (Gymnostomum recurvum Griff., Calcutta J. Nat. Hist. 2: 482, 1842, see discussion of nomenclature by Robinson 1968; Didymodon recurvus (Griff.) Broth; Bryoerythrophyllum recurvum (Griff.) Saito).