Grimmia montana Bruch & Schimp.

8. Grimmia montana Bruch & Schimp. in Bruch et al., Bryol. Eur. 3: 128. 1845 (Fig. 10).

Lectotypus (designated by Cao & Vitt, 1986: 161): germAny: “ Felsen auf dem Donnersberg ”, IV.1843, Gümbel s.n. (BM [BM000670468]!).

5 Grimmia argyrotricha Müll. Hal. in Flora 73: 485. 1890.

Neotypus (designated by Maier, 2010: 224): tAnzAniA: “Kilimandscharo, unter Schnee in Felsspalten nach W. vorspringendem Grat der Mawenzi- Spitze”, 4600 m, 31.X.1893, Volkens 1347 (H-BR!), synonymized by Maier (2010: 224).

Gametophyte. Dioicous. Female: innermost perichaetial leaf 2.7-3.5 mm long, sheathing up to broadest part, at lower third of leaf cells transparent, some rows of hyaline marginal cells vanishing at broadest part, costa small at leaf base, stout in upper part, excurrent to long-excurrent and forming a denticulate hair-point; male plants in separate cushions, perigonia as multifoliose buds terminal or in leaf-axils, often several in one plant, innermost perigonial leaf 1 mm long, strongly sheathing, concave, apex acute or blunt, costa percurrent, paraphyses numerous. Growth form: cushion compact, interwoven with young shoots originating from rhizoids or older stem parts, leaflets appressed to stem, apices slightly patent, plants erect, radiculose at base, stems up to 20 mm high, central strand developed. Lower leaves small, muticous, suddenly longer, 1.8-2.5 mm long, lower part appressed to stem, apical part of longer leaves slightly twisted when dry, slowly bending backwards when moistened, erectopatent when wet, at transitional part from broad, ovate leaf base restricted to lanceolate laminal part, thus forming shoulder, tapering to acuminate apex, hairpoints of variable length, densely and bluntly denticulate; leaf form in situ, concave from leaf base up to upper part of leaf, upper third keeled, margins in laminal part from leaf base up to apical part gradually becomng plane or incurved; basal cells near costa rectangular, towards margin two or three rows of short-rectangular or quadrate cells, walls smooth, transverse walls markedly thicker than longitudinal walls, at margin some rows of hyaline cells, above shoulder at margin a longitudinal row of transversely oval cells, lamina cells small, more or less isodiametric, lumina rounded, lamina cells, seen in transverse section, short-rectangular, exterior cell walls smooth; leaf base unistratose, in transitional part lamina bistratose in places, in upper part bistratose, occasionally unistratose near costa, margin unistratose at leaf base, in laminal part bistratose, below apex occasionally tristratose. Costa, seen on dorsal side, small at leaf base, enlarged, prominent in laminal part, excurrent, costa, seen in transverse section, on dorsal side at leaf base rounded, in lower laminal part prominent, slightly angulate, in upper laminal part rounded, on ventral side at insertion widely channelled, in laminal part channelled or narrowly channelled, at insertion and leaf base 4 guide cells, occasionally enlarged to 5 cells, in laminal part reduced to 2, from insertion to mid-leaf with a central median group of hydroids, transformed to substereids in upper part, vanishing in apical part.

Sporophyte. Seta up to 3.5 mm long, straight, vaginula 0.8 mm long, cylindrical. Capsule emergent, erect, obloid, occasionally slightly asymmetric, smooth, exothecial cells mostly elongated, rarely pentagonal, walls thin or thick, depending on orientation and focusing, curvilinear, stomata none, at orifice several rows of transversely rectangular cells, the two upper rows suggesting a persistent annulus. Calyptra cucullate, covering part of capsule. Operculum conical, rostrate or rostellate, beak straight or oblique, blunt, margin uneven, some rows of small, rounded marginal cells, in conical part larger oval or rounded cells. Peristome teeth erect when dry, lanceolate, irregularly perforated or slit to two unequal branches, lower dorsal part smooth, subsequent plates sparsely covered with fine papillae, upper dorsal and ventral sides densely covered with fine papillae, trabeculae thin, in lower part close together, in upper part distant, slightly protruding. Spores 10-12 µm, smooth.

Diagnostic characters. – Gametophyte. Leaves with cells at basal margin short-rectangular to quadrate, with transverse walls strongly thickened, above shoulder margins with a row of transversely oval cells; in transverse section lamina cells shortrectangular, with exterior cell walls smooth; margins in laminal part plane or incurved.

Distribution, habitat and ecology. – Grimmia montana is widely, but highly disjunctively distributed. In the northern hemisphere, it occurs in the warm and dry western interior of North America, extending south to Mexico and north to a few localities in the Yukon and Alaska, and with a few localities in eastern Canada and Greenland. It also occurs in Europe and adjacent North Africa, including Macaronesia, western and central Asia, and Hawaii. In the southern hemisphere it occurs only in Africa (Tanzania and southern Africa) and New Zealand.

In South Africa and Lesotho (Fig. 2 B) most of the known populations of Grimmia montana are on seasonally wet quartzitic sandstone, often on slabs that receive water from melting snow, in the higher peaks (mostly above 1,500 m, but rarely down to 1,300 m) in the Cape Fold Mountains from the Hantamsberg and Northern Cederberg, south and eastwards to the Swartberg. Two disjunct populations occur on basalt at high altitude (>3,200 m) in the Drakensberg. This species is also likely to be found on the higher peaks of the Great Escarpment in the Eastern Cape; these areas remain bryologically poorly explored.

Notes. – A total of 27 specimens were seen all of which were sterile. In female plants the basal cells may be elongated, and the loss of chlorophyll may give the leaf base a hyaline aspect. In the local specimens available for this study, no sporophytes were found in appropriate condition for the description of their characters.

The name Grimmia argyrotricha Müll. Hal. has been used in various works on the bryophyte flora of Africa, e.g. O’Shea (2006: 92) and Van Rooy & Perold (2006: 15). The type specimen of G. argyrotricha, collected by Dr. Hans Meyer in the Kilimandscharo Massif in 1880 was destroyed at B and a neotype has been selected by Maier (2010: 232).

Selected specimens examined. – South AfriCA. Prov. Western Cape: Citrusdal Area, Cederberg Apex Peak area, 1500 m. 32°35’34”S 19°12’27”E, 9.I.2001, Hedderson 13645 (BOL); Cederberg, Cederberg State Forest, E side of Langberg, 1550-1870 m 32°23’20”S 19°10’25”E, 17.II.2001, Hedderson 13706 (BOL); Cederberg, Sneeuberg, Ridge to NW of main peak, 1500-1700 m, 32°29’58”S 19°08’51”E, 7.IV.2002, Hedderson 14482 (BOL, G); ibid. loc., Hedderson 14491 (BOL); ibid. loc., Hedderson 14501 (BOL); Cederberg Wilderness Area, slopes on West side of Shadow Peak, 1850 m, 32°23’20”S 19°10’25”E, 22.II.2003, Hedderson 14990 (BOL).