35. SCOPELOPHILA Plate 47.

Scopelophila (Mitt.) Lindb., Acta Soc. Sci. Fenn. 10: 269, 1872. Type: Scopelophila ligulata (Spruce) Spruce.

Merceya Schimp., Syn. Musc. ed. 2: 852, 1876. Type: Merceya ligulata (Spruce) Schimp.

Merceyopsis Broth. & Dix. ex Dix., J. Bot. 48: 301, 1910. Type: Merceyopsis pellucida Broth. & Dix., J. Bot. 48: 301, 1910, India, W. Ghats, Panchgani, Sedgwick 35, H, lectotyp. nov.

Weissia sect. Scopelophila Mitt., J. Linn. Soc. Bot. 12: 134, 1869.

Pottia sect. Orthotrichella C. Müll., Gen. Musc. Fr. 392, 1900. Type: Pottia gedeana Lac.

Plants forming a thin or thick turf, greenish yellow to brown above, blackish green or weakly iridescent metallic tan or yellowish brown below. Stems seldom branching and then irregularly, to 4 cm in length, transverse section rounded-pentagonal, central strand absent, sclerodermis absent, hyalodermis absent; axillary hairs 3–5 cells in length, basal cell usually brownish; sparsely radiculose or occasionally with a thick, reddish brown tomentum. Leaves often crowded, incurved to spreading, contorted, usually carinate, occasionally with undulate upper margins when dry, spreading when moist, lingulate to ligulate or oblanceolate, widest at or above midleaf, to 2.5 mm in length, upper lamina narrowly grooved along costa or sometimes broadly channeled, margins plane or somewhat recurved below, entire to minutely crenulate or denticulate above, often bordered by a few rows of thicker walled cells above; apex broadly acute or obtuse, often with a broad apiculus, occasionally rounded; base scarcely differentiated in shape to long-elliptical, occasionally wasp-waisted, occasionally slightly decurrent; costa slender, percurrent or ending up to 2–8 cells below the apex, occasionally excurrent as a short mucro, superficial cells quadrate to rectangular ventrally, short-rectangular to elongate dorsally, 2–4 rows of cells across costa ventrally at midleaf, costal transverse section semicircular to round, one stereid band present, generally well distinguished from the superficial parenchymatous layers, epidermis absent or present ventrally, present dorsally, guide cells 2(–4) in 1 layer, hydroid strand absent; upper laminal cells rounded-quadrate to hexagonal or short-rectangular, ca. 8–14 mm, often heterogeneous in size and shape, 1(–2):1, walls thin to evenly thickened or weakly collenchymatous, thicker near margins, superficially flat or somewhat bulging on ventral surface; papillae lacking, occasionally low-verrucose; basal cells differentiated across leaf, extending higher medially, rectangular, occasionally inflated, scarcely wider than the upper cells to inflated, 2–3:1, walls hyaline or deep brown, bordered on margins by one or more rows of narrow rectangular cells. Propagula rare, on stalks from the stem, greenish brown, clavate to ellipsoidal or filamentous and branching, ca. 12 µm in diameter, of 2 or more rounded cells. Dioicous. Perichaetia terminal, inner leaves little differentiated from the cauline. Perigonia terminal, outer leaves loosely sheathing, inner deltoid. Seta 2–6 mm in length, 1(–2) per perichaetium, brown to yellowish brown, twisted clockwise below; theca 0.6–2.2 mm in length, brown to yellowish brown or blackish, short-elliptical to short-cylindrical, exothecial cells quadrate-hexagonal to rectangular, occasionally bulging, 2–3:1, walls thin, stomates present and commonly difficult to distinguish or often apparently absent, phaneropore, at base of theca; annulus weakly differentiated or of 1–4 rows of vesiculose cells, deciduous in fragments; peristome absent. Operculum conic-rostrate, erect or oblique, ca. 0.7–1.5 mm in length, cells in straight rows. Calyptra cucullate, smooth, ca. 0.8 mm in length. Spores 8–13 µm in diameter, light brown, finely papillose or smooth. Laminal KOH color reaction yellow to yellowish orange. Reported chromosome number n = 13.

Scopelophila is a small genus usually associated with highly mineralized soils, found in mountainous areas of North, Central and South America, Europe, central Africa, Asia and Oceania (Hawaii).

Distinguishing characters of Scopelophila include the stem section of nearly homogenous, wide-lumened cells (Pl. 47, f. 2), lacking sclerodermis, hyalodermis, or central strand, the usually spathulate, oblanceolate leaves often with a distinctive broad apiculus (Pl. 47, f. 4), upper laminal cells lacking papillae and often heterogeneous in size and shape, costal section with a single stereid band imbedded in parenchymatous tissue (Pl. 47, f. 6, 12), and the capsule lacking a peristome. The leaves are often blackish in the lower parts of the plant, and this may be associated with iron ions in the substrate as the leaves of many mosses react with a black coloration to ferric chloride solution.

There is an interesting body of literature (reviewed by Persson 1948, among others, and most recently by Shaw and Anderson 1988) on Scopelophila as a “copper moss,” meaning that it is one of a small number of taxa characteristically found growing in association with copper, zinc and iron ores.

The genus Merceyopsis was created (Dixon 1910) with seven species, apparently as an attempt to group certain eperistomate species (except in the case of M. spathulifolia, the type of which had only fragmentary sporophytes) that are seen here (see also Noguchi 1956) as members of Barbula, Gymnostomum, Hymenostylium, Scopelophila, Trichostomum or Tuerckheimia (see Merceyopsis in the list of recognized taxa for dispositions). Dixon's (1910, p. 298) preliminary discussion of his treatment indicates that the lectotype of Merceyopsis should be M. pellucida Broth. & Dix. ex Dix. (= Scopelophila cataractae (Mitt.) Broth. cf. Noguchi 1956; Zander 1967).

Additional literature: Arts (1988), Bartram (1924b), Corley and Perry (1985), Crundwell (1986), Frahm (1990b), Hoe (1973), Jones (1961), Lampton (1966), Lecointe and Schumacker (1988), Mårtensson and Berggren (1954), Melick (1975), Nagano and Schimizu (1973), Nagano et al. (1969), Noguchi and Furuta (1956), Noguchi and Ochi (1956), Reese (1989), Rumsey and Newton (1989), Satake (1990, 1991), Satake et al. (1988, 1990), Schatz (1955), Schumacker and Brugués (1991), Schumacker et al. (1989), Shaw (1987a,b), Shaw and Anderson (1989), Shaw and Beer (1989), Sotiaux et al. (1987), Takenaka and Satake (1991), Thyssen and Poelt (1958), Zander (1967, 1986b).

Number of accepted species: 3 plus 1 remaining in Merceya.

Species examined: S. cataractae (BUF, DUKE, FH, H, L, MEX, TENN, US), S. infericola (BUF), S. ligulata.

New heterotypic synonymy: Desmatodon africanus P. Varde (PC) = Scopelophila cataractae (Mitt.) Broth.