Schoenus arenicolus T. L. Elliott & Muasya
Creators: name: Elliott, T. L.
name: Muasya, A. M.
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Cyperaceae
Schoenus
Schoenus arenicolus

description: 2. Schoenus arenicolus T.L.Elliott & Muasya in S. African J. Bot. 112: 359 (2017),
non Schoenus brachyphyllus J.M.Black (1929); Tetraria brachyphylla Levyns, J. S. African Bot. 13: 90 (1947). Type: South Africa, Western Cape Province, 3418 (Simonstown); slopes of Kapitein's Peak, Hout Bay, (–AB), 20 Oct 1946, Levyns 8093 (BOL, holo! [BOL139415]; BOL! [BOL139413, BOL139414], K!, PRE!, SAM - image!, iso.)
Tetraria sylvatica var. pseudocuspidata Kük, Repert. Spec. Nov. Regni. Veg. 29: 188 (1931). Type: South Africa, Western Cape Province, 3419 (Caledon); ‘in collibus pone Rhenosterkopp’, (–DD), 28 Apr 1897, Schlechter 10,570 (PRE, lecto.!, here designated; BM!, GRA!, K!, S - image!, P[P00461872, P00461873, P00461874] - image!, WAG[WAG0389326, WAG0108275] - image!, L - image!, isolecto.)
Caespitose, phyllopodic perennial graminoid. Often partly or almost entirely viscous, especially on sheaths and inflorescences. Culms terete, (206–)335–575(− 688) × 0.6–1.0(− 1.5) mm. Leaves basal, 2–5, short, (10.0–)25.0–68.0(− 134.0) × 0.2–0.7(− 1.2) mm, flat, usually not proximally channelled, straight or less often not, margin usually serrate above sheath. Sheaths often reddish-brown colour, smooth, often viscous, tightly clasping culm, longitudinally striate. Ligule membranaceous, 2-lobed, (1.9–)3.5–6.0(− 8.3) mm. In fl orescence a narrow panicle, 9.5–25.5(− 46.0) × (2.5–)4.0–6.0(− 10.0) mm, sometimes viscous, proximal rachis length 5.5–11.5(− 16.0) mm. Proximal primary in fl orescence bracts firm, non-sheathing, 25–77(− 173) mm long, often exceeding length of inflorescence several times, can have small membranaceous extensions at base. Spikes few, 1–5, 7.0–12.0(− 22.0) mm long. Spikelets 5.7–8.2(− 10.0) × 1.0–2.4(− 3.8) mm, usually paired with one sessile and the other with a short pedicel, oblong to lanceolate, 1–3 spikelets/spike. Rachilla 0.2–2.0(− 4.9) mm long. Glumes (1–)3–5 per spikelet, proximal glume (1.6–)2.6–3.2(− 3.6) mm long, subproximal glume 2.4–3.6(− 4.6) mm long, thick, firm, often shiny, distichous, more or less 2- ranked, reddish-brown, sometimes with a narrow scarious margin, upper glumes longer in length, prophylls with notable, raised vein extending to mucro. Mucros well-developed, proximal mucro length (0.1–)0.8–1.4(− 3.0) mm, subproximal mucro length (0.1–)0.5–1.0(− 2.2) mm. Stamens 3(− 9) per floret, anthers 3.3–4.7 mm long. Stigmas (2–)3-branched. Perianth bristles 0. Nutlet smooth below, broad elliptic, slightly trigonous, 3.1–4.9(− 5.8) × 1.5–2.4 mm. Nutlet beak conical, almost smooth, continuous with the lower part of nutlet, with faint longitudinal furrows, (0.5–)1.6–2.0(− 2.6) mm long. (Figs. 1 and 2).
Flowering: September to December
Distribution and ecology: the distribution of S. arenicolus is mostly near the southwestern coast of South Africa, ranging from the Cape Peninsula in the west to the Knysna area in the east (Fig. 4). This species generally grows on well-drained sandy sites among fynbos vegetation at low elevations (sea level to approximately 185 m).
Diagnosis: Schoenus arenicolus can be distinguished from most other species in this group by its reddish-brown leaf sheaths and relatively narrow inflorescences, which often have only three to six spikelets. It is a similar species to S. compar, from which it can be differentiated by its shorter leaves and reddish-brown leaf sheaths as opposed to the ivory sheaths of S. compar. Furthermore, S. arenicolus has much fewer spikes and spikelets, as well as nutlet beaks that are continuous with the nutlet body and smoother compared to those of S. compar.
Additional collections examined
South Africa. WESTERN CAPE: 3318 (Cape Town): Near the Stellenbosch Division, boundary on the Klipfontein Rd., (–DC), 19 Dec 1962, Esterhuysen 29,966 (BOL, K); Klipfontein Road near Duinendal, (–DC), 12 Sep 1943, Levyns 7588 (BOL); Stikland, Cape Flats, dunes near power station, (–DC), 30 Aug 1979, Boucher 4505 (NBG); Cape Flats Nature Reserve – Bellville, University of Cape Town, (–DC), 27 Oct 1978, Low 740 (NBG). 3418 (Simonstown): Sandy flats between Fish Hoek and Noord Hoek, (–AB), Sep 1921, Pillans 4866 (K); Headland at Witsand, (–AB), Jan 1923, Pillans 4777 (K); N of Wildevoëlvlei, (–AB), 24 Nov 1983, O'Callaghan 707 (NBG); Platboom road, Cape Point Reserve, (–AD), 26 Sep 1978, Esterhuysen 35,034a (BOL); The Meadows Cape Point, (–AD), 7 Dec 1965, Taylor 6620 (NU, PRE); dune beyond Gifkommetjie turn-off, Cape of Good Hope Nature Reserve, (–AD), 7 Sep 1972, Taylor 8180 (NBG); Phillipi - Mitchell's plain, (–BA), 23 Aug 1998, Low PM 25 (GRA); Swartklip Road, (–BA), 9 Aug 1991, Berry 18 (NBG); Betty's Bay, Hangklip Estates, (–BD), 7 Feb 1944, Levyns 7668 (BOL); Hangklip Subregion, Blesberg lower slopes along vehicle track, (–BD), 4 Mar 2001, Joubert 435 (NBG); Buffels River mouth, Pringle Bay, (–BD), 17 Nov 1971, Boucher 1743 (NBG). 3419 (Caledon): Wortelgat (Dadelkom), (–AD), 28 Sep 1988, B ӧsenberg & Rutherford 412 (NBG); Hermanus, 3 km SE of Gansbaai, Suikerbosrand, (–CB), 11 May 2005, Helme 3475 (NBG);Groot Hagelkraal, (–DA), 8 Mar 2012, Muasya 6477 (BOL); Buffeljacht farm, south of Buffeljagsberg, (–DA), 12 Mar 1979, Thompson 3962 (NBG, PRE); Rattle River Mouth, ± 8 km E of ‘Die Dam’, E side of mouth, c. 800 m from coast; (–DC), 7 Jun 1984, O'Callaghan, Fellingham & van Wyk 459 (NBG). 3420 (Bredasdorp): De Hoop Nature Reserve, (–AD), 11 Apr 1957, Levyns 10,706 (BOL [2 sheets]); De Hoop, Potberg Nature Reserve, Potberg farm, 2 km from coast along track to coast, (–BC), 9 Jul 1978, Burgers 1076 (K, NBG, PRE); Bredasdorp, Struisbaai, 2 km NW of Molshoop, (–CA), 28 Apr 2003, Helme 2668 (NBG); Agulhas, (–CC), 10 Apr 1948, Levyns 8821 (BM, BOL). 3421 (Riversdale): Brandfontein, (–AB), 13 Oct 1951, Esterhuysen 18,993 (BOL); 2 km from Duivenhoks river mouth, W side, (–BD), 28 May 1984, O'Callaghan, van Wyk & Fellingham 394 (NBG). 3422 (Mossel Bay): Goukamma Nature Reserve, (–BB), without date, without collector 163 (K). 3423 (Knysna): Robberg, Plettenberg Bay, (–AB), 25 Oct 1955, Esterhuysen 25,009 (BOL, K); Plettenbergbaai, Robberg, (–AB), Apr 1975, Viljoen 105 (PRE).
description: Published as part of 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 *, pp. 303-315 in South African Journal of Botany 114 on page 308, DOI: 10.1016/j.sajb.2017.11.020, http://zenodo.org/record/10496511