Grimmia pulvinata (Hedw.) Sm.

10. Grimmia pulvinata (Hedw.) Sm. in Engl. Bot. 24: 1728. 1807 (Fig. 12).

[Fissidens pulvinatus Hedw., Sp. Musc. Frond. 158. 1801.

Lectotypus (designated by Cao & Vitt, 1986: 191): Sine loC.: “In tectis et muris vulgaris, vere maturans”, s.d., Anon. s.n. (G [G00040350]!).

5 Fissidens pulvinatus var. africanus Hedw., Sp. Musc. Frond. 159. 1801.

Lectotypus (designated by Muñoz, 1999: 168): South AfriCA: “Ad Cap. bonae spei lecta, specimina misit O. Swartz”, s.d., Swartz s.n. (G [G0004035]!), synonymized by Magill (1981: 275).

5 Grimmia ecklonii Spreng., Syst. Veg. 4: 321. 1827.

Lectotypus (designated by Muñoz & Pando, 2000: 67): South AfriCA: Swellendam, s.d., Ecklon s.n. (BM [BM000575940]!; isolecto-: BM [BM000670219]!), synonymized by Muñoz & Pando (2000: 67).

Gametophyte. Monoicous. Female: innermost perichaetial leaf 2.2-2.5 mm long, sheathing up to apical part, tubulose, hyaline in lower part of leaf, costa excurrent to long, bluntly denticulate hair-point; male: perigonium as bud of 4 or 5 leaves, on short stalk in leaf axil on stem of fruiting plant, close to perichaetium, innermost perigonial leaf 1 mm long, sheathing up to apex, concave, ovate, apex acute or mucronate, costa vanishing below apex, hyaline except at apex, paraphyses few. Growth form: cushion dense, lax, young shoots originating from detritus, leaflets with hair-point, plants radiculose at base, erect, dichotomously branched, stems up to 15 mm high, central strand developed. Leaves in lower part of stem small, with hair-point, becoming gradually longer, up to 2.5 mm long, crowded, loosely disposed on stem, upper part of leaf slightly flexuose when dry, especially the comal ones, apical part quickly bending backwards when moistened, erecto-patent when wet, broadest part of leaf in lower third, broad-lanceolate or lanceolate from a short, ovate leaf base, apex obtuse, hair-point denticulate; leaf form in situ, leaf base widely concave or concave, laminal part widely keeled, margin recurved on one side from insertion or leaf base up to above mid-leaf, rarely on the other side and then, at most, in the middle of the leaf; in leaf base some paracostal cell rows of slightly elongate-rectangular cells, walls smooth, towards margin cells short-rectangular, at margin one or two rows of rectangular cells which may appear hyaline, transverse walls thickened, all cell walls smooth, in transitional part cells rectangular, walls sinuose, in laminal part mostly isodiametric, walls somewhat sinuose, thickened, at apex cells isodiametric, lumina rounded; lamina, seen in transverse section, unistratose, margin at insertion and leaf base unistratose, in laminal part, at least in the very apical region, several marginal cell rows are bistratose on both sides or on one side only, even completely unistratose margins may be seen. Costa, seen on dorsal side, of nearly uniform width, faintly smaller in leaf base, percurrent, seen in transverse section, on dorsal side rounded, on ventral side at insertion and leaf base slightly concave, in laminal part above widest part of leaf widely channelled, at insertion and leaf base 4 guide cells, in laminal part reduced to two, at insertion and leaf base a small band of substereids or stereids and a median group of hydroids, gradually vanishing up to apical part.

Sporophyte. Seta up to 4.5 mm long, erect, twisted when old and dry, in immature and mature state arcuate or curved when wet, vaginula 0.8 mm long, cylindrical. Capsule erect when old, in immature and mature state pendent and hidden in cushion, obloid, in mature state with eight to ten ribs, exothecial cells elongated, walls curvilinear, thin, stomata numerous in short apophysis, annulus of three or four rows of cell, detaching in a spiral, cells of capsule at orifice with crenulate outer walls. Calyptra mitrate, lobed, covering upper part of capsule. Operculum with straight beak of variable length, margin crenulate, a marginal row of oval cells, cells in conical part mostly elongated of different shape. Peristome, teeth erectspreading when dry, broad at base, elongate-lanceolate, in upper half split into two or three divisions, separated down to insertion, dorsal side smooth near insertion, the upper part of dorsal side and ventral side densely covered with fine papillae, trabeculae thin, neared, slightly protruding. Spores 8-11 µm, granulose.

Diagnostic characters. – Gametophyte. Leaves broadest in the lower third; margin recurved on one side from insertion or leaf base up to above mid-leaf, rarely so on the other side, and if so only in the middle of the leaf; leaf with one or two basal paracostal cell rows rectangular, towards margin cells short-rectangular, at margin one or two rows rectangular with thickened transverse walls which may appear hyaline, all cell walls smooth.

Distribution, habitat and ecology. – Grimmia pulvinata is a very widespread species that occurs on every continent except Antarctica. It is often common in temperate areas of the northern hemisphere, with some extensions northward into boreal zones, and (rarely) southward to subtropical areas. In the southern hemisphere this species is recorded from Australia, New Zealand, southern South America (Chile and Uruguay), and from southern Africa. Although frequently considered cosmopolitan, it is actually largely absent from the tropics and subtropics. In sub-Saharan Africa, for example, it appears to be largely restricted to the study area and adjacent Namibia, and is not recorded for any other country on the continent except Ethiopia. It is thus probably better considered a temperate species with some poleward extensions.

In South Africa and Lesotho (Fig. 2 D), G. pulvinata is one of the two most common species of Grimmia encountered. It occurs over a broad altitudinal range (50 to 1,910 m), and in most of the major biomes, except for the various savannah and tropical thicket and forest types. Most collections are from quartzitic sandstones, but it also occurs on most other rock types (e.g. shales, granites, basalt) present in the region.

Notes. – A total of 167 specimens were seen of which 67 had sporophytes, although only 6 had capsules that were in a suitable state for examination whilst 9 were immature, and the remaining 52 were decomposed. The leaf shape in Grimmia pulvinata is variable. Leaves can vary from short ovatelanceolate to elongated ovate-lanceolate, and small lanceolate forms also appear.

The hair-points can be longer than the lamina, whilst at the other extreme some plants have leaves with only a few hyaline cells at the apex or even lack the hair-point altogether. A specimen from the summit of the Zuurberge Range (Alexander s.n., BOL) where all leaves are muticous was annotated by Dixon as “ G. pulvinata var. submutica ”, a name that was never published.

The stratosity of the leaf margins is variable. In different leaves, even on the same plant, unistratose or bistratose margins may be observed. For the correct identification of G. pulvinata, and for its differentiation from G. orbicularis, the stratosity of the leaf margins is thus not very useful. A stable distinguishing character is provided by the paracostal cell rows in the leaf base. In G. pulvinata these (Fig. 12 F, G) are slightly elongate-rectangular, becoming short-rectangular towards the margins and all cell walls are smooth. In G. orbicularis on the other hand (Fig. 11 E, F), these are elongate-rectangular, with nodulose walls towards the costa, but rectangular to quadrate with smooth walls at the margins.

Other species have been subject to frequent misidentification as G. pulvinata, and amongst the material at BOL and PRE specimens of G. consobrina, G. fuscolutea, G. laevigata, and G. pygmaea were found to have been erroneously attributed to G. pulvinata.

Grimmia pulvinata grows from 250 to 2,000 m in Europe and North America (records from above 2,000 m should be checked), from 1,000 to 1,800 m in Asia, and from 50 to 1,910 m in South Africa. Grimmia pulvinata thus seems to be restricted to altitudes from sea level to 2,000 m across its range.

Selected specimens examined. – South AfriCA. Prov. Western Cape: Cape Peninsula, Silvermine NR, Silvermine Valley, just above “Sunbird Environmental Recreation Centre”, 34°06’28”S 18°24’37”E, c. 50 m, 6.IV.2000, Hedderson 13148 (BOL); Ceres District, Oliphants River Mountains. Beaverlac area, Ratel’s River, c. 400 m, 32°54’27”S 19°04’01”E, 8.I.2001, Hedderson 13601 (BOL); Citrusdal Region, Cederberg, Cederberg State Forest, Welbedacht Kloof, 900- 1300 m, 32°24’30”S 19°10’24”E, 17.II.2001, Hedderson 13677 (BOL); c. 4 km along R355 from intersection with R46 between Ceres and Touwsrivier Steep, c. 850 m, 33°11’10”S 19°47’05”E, 4.VI.2001, Hedderson 13851 (BOL).