Grimmia longirostris Hook.

7. Grimmia longirostris Hook.

, Musc. Exot. 1: 62. 1818

(Fig. 9).

Lectotypus (designated by Deguchi, 1984: 21): eCuAdor: sine loc., s.d., Humboldt 76 [H 2669] (BM [BM000671051]!; isolecto-: BM [BM000670951]!).

Gametophyte. Mostly monoicous. Female: innermost perichaetial leaf up to 4 mm long, sheathing up to 2/3 of leaf length, leaf base elongated, in broadest part suddenly narrowed to subulate apical part, at margin, from insertion up to broadest part of leaf, a broad band of hyaline cells present, vanishing gradually in upper leaf, costa excurrent in denticulate hair-point; male: perigonia not seen. Growth form: in dense cushions, adherent to substrate with rhizoids, from which young shoots with scale-like leaflets originate, apices patent, muticous, acute, plants erect, branched, radiculose at base, stems up to 30 mm high, central strand well-developed. Lower leaves scale-like, upper stem leaves up to 3 mm long, loosely disposed on stem, apices may be contorted, imbricate when dry, bending backwards when moistened, erecto-patent when wet, from ovate base gradually narrowed to lanceolate lamina, tapering to acute apex, hair-point short, faintly to strongly denticulate; leaf form in situ, at base concave, one side plicate, in laminal part keeled, narrowly so below apex, margin on larger side from insertion up to mid-leaf recurved or revolute, other side mostly plane; basal paracostal cells elongate-rectangular, walls nodulose, thickened, transverse walls thin, often oblique, cells near margin quadrate to rectangular, walls smooth, transverse walls thickened, in some specimens hyaline up to broadest part of leaf, in transitional part paracostal cells short-rectangular, walls thickened, nodulose or smooth, upper lamina cells rounded-quadrate, walls thickened, faintly sinuose; seen in transverse section, basal cells unistratose, in transitional and lower laminal part uni- to bistratose, in upper part bistratose, at margin several rows of cells bistratose except at leaf base. Costa, seen on dorsal side, of nearly uniform breadth, slightly smaller at insertion, obscure in keeled part, percurrent, seen in transverse section, costa on dorsal side at insertion and leaf base widely rounded, in lower laminal part unevenly rounded, somewhat angulate, and slightly contracted at origin of lamina, becoming indistinct in upper laminal and keeled part, on ventral side at insertion and leaf base widely channelled, in laminal part channelled, at insertion and leaf base 6 guide cells, rarely only 4, in upper part 5 or 4, in indistinct part 2 guide cells, from insertion up to indistinct part a central band of stereids or substereids, occasionally a central group of hydroids, vanishing in upper part of leaf.

Sporophyte. Seta straight, 1-5 mm long, vaginula 0.9- 1.2 mm long, cylindrical, with ochrea. Capsule exserted, emergent or immersed, erect, cylindrical, oblong-ovoid, with short neck, narrowed at orifice, smooth, in immature state shrivelled, exothecial cells multiform, elongated, walls curvilinear, stomata at transition above neck and at base of capsule, annulus of three or four rows of cells, detaching in a spiral. Calyptra mitrate, mostly with a single slit, covering upper third of capsule. Operculum rostellate, beak straight or slightly oblique, margin crenulate, one or two rows of rounded marginal cells, in conical part rhombic, rounded-rectangular, thick-walled. Peristome erect when dry, teeth lanceolate, entire or split into two or three branches, on dorsal side two or three plates smooth, the consequent dorsal part covered with fine papillae, the upper third of dorsal side and ventral side densely covered with conspicuous papillae, trabeculae small in lower part, thin in upper part. Spores 10-12 µm, smooth.

Diagnostic characters. – Gametophyte. Leaf apically keeled, margin recurved on broader side. Costa, in lower part of lamina, unevenly rounded, somewhat angulate.

Distribution, habitat and ecology. – Grimmia longirostris is a very widely distributed species that is often associated with montane or sub-montane habitats in temperate and arctic regions. This species is found on all continents except Antarctica. It also occurs widely throughout the tropics in higher mountain systems.

In South Africa and Lesotho (Fig. 2 A) this species is restricted to the high Drakensberg (1,860-3,370 m) and associated ranges, where it occurs on basalt in high-altitude grasslands.

Notes. – A total of 56 specimens were seen, 16 with sporophytes but only 4 with capsules in a suitable state for examination, 3 were immature and 9 were decomposed. Misidentifications of this species appear largely to be responsible D for the persistent records of G. ovalis (Hedw.) Lindb. from South Africa, (see under Excluded species for South Africa and Lesotho below). A syntype of Grimmia longirostris is extant at G [G00281576]).

Selected specimens examined. – South AfriCA. Prov. Natal: Bergville Dist., Mnweni area, Drakensberg, 2740 m, VII.1953, Esterhuysen 21637 (BOL); Bethlehem Division, Drakensberg, Mont-aux-Sources, Crows’ Nest, VII.1947, Schelpe 2116 (BOL [3 specimens]); Drakensberg: Umgatsheni valley S aspect bank, c. 2130 m, s.d., Esterhuysen 35931 (BOL).