Schoenus megacarpus T.L.Elliott & Muasya, 2018

Elliott, T. L. & Muasya, A. M., 2018, A taxonomic revision of Schoenus compar - Schoenus pictus and allies (Cyperaceae, tribe Schoeneae) with three new species described from South Africa *, South African Journal of Botany 114, pp. 303-315 : 312-313

6. Schoenus megacarpus T.L.Elliott & Muasya , sp. nov.

Type: South Africa, Western Cape Province, Ladismith (3321): north side of Garcia's Pass, along road to Langkloof , approximately 6 km along road, below powerline, (–CD), 8 Jul 2017, Elliott & Muasya TE 2016_219 (BOL!, holo.; MT!, NBG!, iso.).

Caespitose, phyllopodic perennial graminoid with flat leaves. Not viscous. Culms terete, (203–)425–510(− 712) × 0.3–1.2(− 2.3) mm. Leaves basal, 2–5, flat, firm, not channelled, (24–)146–185(− 215) × 0.2–0.7(− 1.2) mm, up to or exceeding half of culm length, apices rounded, margins serrate. Sheaths open, papery, often reddish-purple, but can be almost entirely ivory in colour, not viscous. Ligule membranaceous, (2.2–)4.3–7.4(− 10.5) mm. In fl orescence a compact spike-like panicle, (14.5–)23.0–39.5(− 54.5) × 5–10(− 14) mm, not viscous, proximal rachis length (2.5–)6.5–13.0(− 23.0) mm. Proximal primary in fl orescence bracts sometimes envelope entire spikes, lower two to three notably expanded at base with membranaceous extensions on edges, longitudinal veins evident, lowest 31–75(− 100) mm long, flat, apices rounded. Spikes few, 2–5, 7.0–17.0(− 23.0) mm long. Spikelets (5.2–)8.8–11.2(− 13.2) × (0.6–)1.7–2.3(− 3.5) mm, with pedicels, 2–5 spikelets/spike. Rachilla (0.4–)1.4–2.3(− 6.4) mm long. Glumes 4–7 per spikelet, proximal glume (2.2–)2.9–5.7(− 12.6) mm long, subproximal glume (2.9–)3.8–9.5(− 13.1) mm long, thick, firm, more or less 2-ranked, reddish-brown, with or without a narrow scarious margin, upper glumes longer in length, apices acute or acuminate. Mucros sometimes present, proximal mucro (0–)0.2–0.6(− 1.2) mm long, subproximal mucro (0–)0.1–0.4(− 0.9) mm long. Stamens (2–)3 per spikelet, anthers 4.0– 5.6 mm long. Stigmas (2–)3 branched. Perianth bristles 3, shorter than glumes. Nutlet relatively large for clade, 3.2–6.2(− 7.3) × 1.2–2.4(− 3.1) mm. Nutlet beak 1.0–2.7(− 3.4) mm long ( Figs. 1 and 2 ).

Flowering: February to May

Distribution and ecology: Schoenus megacarpus is generally a species of the south-central region of South Africa, with specimens having been collected from as far west as the Anysberg Nature Reserve and as far east as the Grahamstown area ( Fig. 8 ). The northern limit of distribution of this species is in the Groot Swartberg Nature Reserve. This species generally grows on relatively high elevation mountain slopes (above 1000 m) among fynbos vegetation in the western part of its range; however, in the east it often grows among grassland vegetation at lower elevations (approximately 100–200 m).

Diagnosis: The spikelets and nutlets tend to be longer in S. megacarpus compared to other species in this group. Schoenus megacarpus is most similar in morphology to S. compar ; however, it lacks the viscous culms and inflorescences of S. compar . In addition, the base of its culms are often reddish, as opposed to the ivory culms of S. compar . Furthermore, whereas the primary inflorescence bracts of S. megacarpus are expanded proximally and have membranaceous extensions, those of S. compar are firm and tend to lack such extensions.

After a careful review of S. megacarpus specimens, we were not able to differentiate specimens collected from mountainous fynbos in the western part of the species range and those collected from lower elevational grasslands to the east.

Additional collections examined

South Africa. WESTERN CAPE: 3319 (Worcester): Onklaarberg, 20 miles south of Worcester, (–DC), Apr 1925, Marloth 6643 (NBG, PRE), Marloth 6460 (PRE). 3320 (Montagu): S slopes of the Aynsberg, Little Karoo, (–AB), 21 May 1950, Esterhuysen 17,039 (K, NBG); Anysberg mountain, next to forestry track on northern slope of mountain, (–BC), 8 Feb 1987, Viviers, Vlok & Bond 290 (PRE [2 sheets]). 3321 (Ladismith): Gauka Mountain (upper slopes), Calitzdorp, (–BC), 25 Apr 1976, Boschoff P342 (NBG); S slopes of the Roodeberg, (–CB), 24 May 1950, Esterhuysen 17,186 (K, NBG, PRE); Garcia Forest Station, lower slope of the Langeberg, (–CC), 25 May 1950, Esterhuysen 17,227 (K). 3322 (Oudtshoorn): Cango Caves, Swartberg Mountains, next to Swartberg Pass, (–AC), 22 Jun 1986, Vlok 1497 (PRE); Swartberg, (–AC), May 1926, Pocock S173 (K [2 sheets], NBG [2 sheets]); Eight Bells Property, (–CC), 12 May 1982, Getliffe 1137 (NU). EASTERN CAPE: 3324 (Steytlerville): Baviaanskloof, Enkeldoorn track, (–CB), Feb 1977, Bond 945 (PRE); Baviaanskloof, Smithkraal-Enkeldoorn track, (–CB), 16 Jan 1978, Bond 1298 (PRE); 11.2 miles W. of Humansdorp on Karredouw road, (–DC), 1 Jun 1960, Acocks 21,083 (K). 3325 (Port Elizabeth): Zuurberg National Park, Skurwenek, near centre of Sondags River Reserve, (–AD), 3 Apr 1986, van Wyk & van Wyk 1499 (PRE); Waaicken Farm, Kantiens Catchment basin, (–CA), 7 Apr 1974, Scharf 1324 (K); ‘In collibus arenolis ad Zwartkop river Z4428’, (–CB), Nov without year, Zeyher 12,613 (NBG); Van Stadens Flower Reserve, (–CC), 16 Apr 1971, Dahlstrand 2742 (GRA); Malabar, above asphalt factory, (–DC), without date, Getliffe 1160 (NU). 3326 (Grahamstown): Kloof 3 mls S. of Grahamstown, E. of Howieson's Poort, (–AD), May 1949, Martin 2906 (GRA); Osmunda Kloof, Grahamstown, at the head of the valley, (–BC), 1 May 1949, Martin 2906 (GRA); Kloof entering Harison's Poort from SE about 4 mls from G.Town, (–BC), 25 Sept 1954, Martin 3103 (GRA); Osmunda Kloof, head of kloof, (–BC), 25 Sept 1949, Martin s.n. (GRA); Hopewell, (–BD), 2 Jan 1945, Acocks 11,118 (PRE); Alexandria, Bushman's River Poort, (–CB), 5 Jan 1956, Archibold 6143 (GRA); between Narraway and Longford Grange; above Bushman's River, (–CB), 23 Oct 1955, 23 Oct 1955, Martin 8227 (GRA).

Figures

Fig. 1. Examples of plants from each of the seven known species of S.compar - S.pictus group found in southern Africa, showing the corresponding inflorescences and spikelets beneath each plant:A,H and O—S.compar; B,I and P—S.arenicolus, C,J and Q—S.pictus; D,K,and R—S.pseudoloreus; E,L and S—S.aureus; F,M and T—S.megacarpus; and G,N and U—S.filiculmis. The black scale bar beside the inflorescences and spikelets in H—N represents 10 mm, whereas the scale bar beneath O—U represents 1 mm.

Fig. 2. Examples of nutlets from six species of the S. compar - S. pictus group found in southern Africa: A—S. compar; B—S. arenicolus; C—S. pictus; D—S. pseudoloreus; E—S.aureus (immature); and F—S. megacarpus. The black scale bar represents 1 mm.The mature fruit of S.filiculmis is unknown.

Fig. 8. Documented locations of Schoenus megacarpus.