Schoenus graciliculmis T.L.Elliott & Muasya, 2020

Elliott, T. L. & Muasya, A. M., 2020, A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae) - Part 2, South African Journal of Botany 130, pp. 327-347 : 342-343

7. Schoenus graciliculmis T.L.Elliott & Muasya , sp. nov.

Type: South Africa, Eastern Cape Province, 3326 (Grahamstown): Featherstone Kloof , ca. 30 m downslope from small vehicle trail, (‒BC), 8 Nov 2017, Elliott & Betz TE2016_254 ( BOL!, holo.; MT!, iso.).

Caespitose, phyllopodic perennial graminoid with relatively narrow leaves and culms ( Fig. 4B ). Culms terete, relatively narrow, (119 —)296 — 360(— 590) X 0.2 — 0.7 mm. Leaves basal, relatively narrow, often over half of culm height, 1 — 4, 110 — 236(— 405) X 0.2‒0.6 (— 0.7) mm, usually proximally channelled, margin serrate above sheath, usually straight. Sheaths reddish-black at base but paler above, firm, longitudinally striate. Ligule firm, relatively short, 0.1 — 0.5(— 0.7) mm long. In fl orescence a thin pseudolateral panicle, dark reddish-brown in colour, mucros from prophylls and glumes evident (prophyll mucros evident especially after disarticulation of spikelets), (11 —)20‒31(— 38) X 1.5‒4.4(— 6.0) mm, proximal rachis length (2 —)8‒12(— 20) mm ( Fig. 4F ). Proximal primary in fl orescence bracts thin, apex acuminate, usually not channelled, narrow at base, (26 —)38‒66(— 92) mm long, exceeding length of inflorescence up to several times. Spikes scattered along inflorescence with little aggregation of spikes into clusters, relatively few, 2‒5, 7‒10(— 14) mm long, slightly overlapping. Spikelets linear-lanceolate to lanceolate, (3.0 —) 4.0‒4.9(— 5.6) X (0.6 —)0.9‒1.3(— 1.7) mm, pedicellate, 2 — 11 spikelets per spike, aggregated into thin spikes, dark reddish-brown in colour ( Fig. 5G ). Proximal spikelet prophyll 1 per spikelet, well-developed, with notable, raised vein extending to mucro, 0.2‒0.5(— 1.6) mm long, mucro often long, (1.1 —)2.2‒3.8(— 8.1) mm. Rachilla (0.3 —)1.0‒ 2.0(— 4.7) mm long. Glumes 4‒8 per spikelet, first three glumes aristate, proximal glume (0.6‒)1.0‒1.6(— 2.0) mm long, subproximal glume (0.5‒)1.1‒1.8(— 2.5) mm long, narrow hyaline margins, upper glumes longer than basal ones, apex acuminate to obtuse. Glume mucros often relatively long, proximal mucro (0.1‒)0.4‒1.5(— 2.4) mm long, subproximal mucro (0‒)0.2‒0.9(— 3.5) mm long. Stamens 1‒3 per floret (usually 3), anthers (1.6‒)2.0‒2.4(— 3.5) mm long. Stigmas usually 3-branched (one 4-branched stigma observed), vestigial stigmas of second bisexual floret absent (i.e. yet to be observed). Perianth bristles absent (i.e. yet to be observed). Nutlet broad elliptic, trigonous, yellowish in colour when young but maturing darker, 2.2‒2.7 (— 3.1) X (0.8‒)1.0‒1.1(— 1.4) mm ( Fig. 6G ). Nutlet beak (0.3‒) 0.6‒ 1.2 mm long.

Flowering: July to December. However, one specimen was observed flowering in February.

Distribution and ecology: Schoenus graciliculmis is a species of the southern Eastern Cape Province and the adjacent areas of the Western Cape Province of South Africa ( Fig. 14 ). This species has been collected from elevations near sea level to over 1600 m, often in wet areas. Many specimens of S. graciliculmis have been collected from grassland slopes; however, some also come from renosterveld and fynbos vegetation types.

A specimen collected by Rear-Admiral H. Lynes in 1937 (BR; Lynes 1467) from the Uasin Gishu Plateau region of Kenya closely resembles S. graciliculmis . The specimen was collected from a young plant with developing spikelets, so it is impossible to confirm that it completely fits within the morphologically circumscription of S. graciliculmis .

Diagnosis: Schoenus graciliculmis is a relatively thin species with leaves that are usually over half the culm height ( Fig. 4B ). In addition, the lower spikelet glumes of this species are aristate ( Fig. 5G ). The distribution of S. galpinii overlaps that of S. graciliculmis in and around the Amathole Mountains in the Eastern Cape Province of South Africa; however, the two species can be differentiated by their spikelets: S. galpinii has cuspidate spikelets ( Fig. 5E ), whereas the spikelets of S. graciliculmis are aristate ( Fig. 5G ). In addition, S. galpinii is generally more of a robust plant with leaves that are often less than half the height of the culm ( Fig. 3E ). The eastern range limit of S. cuspidatus also overlaps with S. graciliculmis (e.g. Featherstone Kloof near Grahamstown), but similar to S. galpinii , the eastern form of S. cuspidatus is more robust with leaves generally less than half the culm height, and it has cuspidate spikelets ( Figs. 4A and 5F ).

Farther to the west, S. quartziticus resembles S. graciliculmis in habit (i.e. it is a relatively thin plant with narrow leaves), but S. quartziticus tends to have scarious glumes compared to the thicker, more dark brown glumes of S. graciliculmis (see Elliott et al., 2019). Furthermore, collections of S. cuspidatus from some of the mountainous areas (e.g. near Stellenbosch and Paarl) in the Western Cape Province of South Africa closely resemble S. graciliculmis in most vegetative and morphological characters; however, there are slight differences in spikelet shape with S. cuspidatus having more cuspidate spikelets compared to the aristate spikelets of S. graciliculmis .

Pseudo-vivipary has been observed in S. graciliculmis (Elliott & Betz TE2016_069).

Additional collections examined

South Africa. EASTERN CAPE: 3226 (Fort Beaufort): Elandsberg , (— BD), 17 Jan 1986, Edwards, Cadman, & Norris ( NU) ; King Williamstown Div., top of Michel's Pass, Hogsback , (— DB), 27 Oct 1946, Esterhuysen 13,237 ( BOL, K); summit of Gaika's Kop , (— DB), 28 Apr 1962, Lubke 361 ( GRA) ; Amatole Mountains, below Gaika's Kop , (— DB), 12 Mar 1982, Furness & Phillipson 118 (K, PRE) ; 9 km N. of Hogsback, Elandsberg, Glenara 155, (— DB), 13 Dec 2016, Helme 9094 ( BOL) ; Amathole Mountains, along P0703 ( Michel's Pass road), ca. 1.75 — 2.0 km to W. of turn-off with R345, (— DB), 6 Nov 2017, Elliott & Betz TE 2016_248 ( BOL) ; Amathole Mountains, lower S. slopes of Gaika's Kop, 400 — 500 m from old lookout on Amathole Forestry Company land, (— DB), 6 Nov 2017, Elliott & Betz TE 2016_250 ( BOL) ; Amathole Mountains, public land managed by Amathole Forestry Company, on edge of Pine plantation Block X11, (— DB), 6 Nov 2017, Elliott & Betz TE 2016_251 ( BOL) . 3227 (Stutterheim): Amatole mountains , between middle and S. Hogsback peaks, (— CA), 24 Apr 1982, Phillipson 562 (K). 3228 (Butterworth): pastures near Kei Mouth, (— CB), Aug 1891, Flanagan 926 ( BOL) . 3323 (Willowmore): Die Hoek, N. side of Zitzikamma Mts, near Joubertina , (— DC), 6 Nov 1949, Esterhuysen 16,387 ( BOL [2 sheets], GRA, NBG). 3324 (Steytlerville): Baviaanskloof, on ridge just above the old lands on Enkeldoring Plateau, Plot #71, (— CB), 22 Sep 2011, Euston-Brown 1301 ( NBG) ; Assegai Bosch , (— CD), 1 Aug 1912, Rogers 2809 ( NBG) ; Cockscomb Peak, S. side of peak on ridge around 1000 m, (— DB), 17 Feb 2016, Euston-Brown 4578 ( BOL) ; Loerie , between Hankey and Loerie, near a large cableway, (— DD), 3 Feb 1996, Sonnenberg 499 ( NU) . 3325 ( Port Elizabeth ): Suurberg Mountains, W. parts, (— AD), 20 Apr 1979, Campbell 13,665 ( NBG) ; ‘ prope Port Elizabeth , monte "Zuurberg"’, (— BC), 1930 without month, Fries 599 ( BOL) ; E. Ridge, Zuurberg Inn , (— BC), 21 Sep 1953, Johnson 728 ( GRA, PRE) ; Zuurberg above Ann's Villa , Somerset E. Div., (— BD), 31 Oct 1945, Acocks 12,020 ( PRE) ; Driftsands, University Campus , (— DC), 21 Oct 1971, U.P.E. Botany Staff 154 ( GRA) . 3326 (Grahamstown): Coldstream , (— AD), 6 Sep 1902, Sole & Daly 253 ( GRA) ; Grahamstown, kloof S.E. of Howieson's Poort , (— BC), 19 Feb 1950, Rhodes University 3128 ( BOL) ; Grahamstown Nature Reserve , (— BC), Nov 1951, Rhodes University 3396 ( BOL) ; 4 Oct 1952, Rhodes University 3404 ( BOL) ; without date, Martin 9639 ( GRA) ; Featherstone Kloof, (— BC), 12 Aug 1961, Lubke 162 (K); Grahamstown area, along one of smaller ravines leading to Featherstone Kloof, (— BC), 11 May 2016, Elliott & Betz TE 2016_065 ( BOL) , Elliott & Betz TE 2016_066 ( BOL) , Elliott & Betz TE 2016_067 ( BOL) ; Grahamstown area, Featherstone Kloof , ca. 30 m downslope from small vehicle trail, (— BC), 8 Nov 2017, Elliott & Betz TE 2016_255 ( BOL) ; 31.4 km from Bathurst on road to Grahamstown, (— BD), Oct 1973, Arnold 614 (K); Round Hill ( Oribi Reserve ), (— BD), 18 Jul 1985, Wirminghaus 363 ( GRA) ; Bathurst, Round Hill , (— BD), 11 Sep 1985, Vengadajellum 67 ( GRA) ; Albany area, near Shaw Park , (— BD), 9 Oct 2006, Verboom 1170 ( BOL) ; 31.4 km from Bathurst on road to Grahamstown , (— BD), Oct 1973, Arnold 614 ( NU, PRE) ; Farm Longford Grange, Bushman's R. Grahamstown , (— CB), Oct 1955, Martin 8228 ( BOL) ; ca. 2 miles N.W. of Martindale , (— DA), Oct 1955, Rhodes University 8229 ( BOL) , Martin 8230 ( BOL) ; Forestdale-Martindale road, ca. 2 miles N.W. of Martindale , (— DA), 30 Oct 1955, Martin 8229 ( GRA) , Martin 8230 ( GRA) , Rhodes University 8230 (K). 3327 (Peddie): Keiskama , near Sontag’ s plot, (— AA), 22 Mar 1950, Acocks 15,727 (K); 11.2 miles W.S.W. of East London , (— BB), 21 Nov 1961, Acocks 21,843 (K, PRE) . 3424 (Humansdorp): Humansdorp , (— BB), 8 Dec 1936, Lynes 1083 ( BM) . WESTERN CAPE: 3321 (Ladismith): Ladysmith , (— AD), 12 Aug 1948, Levyns 9014 ( BOL) ; Ladismith , kopje 2 miles from town, (— AD), 21 Aug 1948, Levyns 9115 ( BOL) ; Roodeberg, Little Karoo , (— DA), 6 Jul 1937, Levyns 6080 ( BOL) . 3322 (Oudtshoorn): Uniondale Div., lower S.E. slopes of Kammanassie Mts. at Laudina , (— DB), 9 Nov 1949, Esterhuysen 16,454 ( BOL, NBG) ; Kammanassieberg, Mannetjiesberg plateau, along road, (— DB), 11 Oct 2006, Verboom 1157 ( BOL) ; between Ruigte Vlei and Barrington, Knysna , (— DC), 13 Jul 1955, Levyns 10,308 ( BOL) . 3323 (Willowmore): Witteberg, peak N. of farm ‘ Worlds View’ , (— BA), 4 Jul 1987, Viviers & Vlok 207 ( WAG) . 3422 (Mossel Bay): 31 miles W. of Knysna , (— AB), 19 Jul 1937, Lynes 1467 ( BM) ; George , (— AB), 15 Oct 1938, Lynes 1792 ( BM) ; George, Gwaing River , top of cliff at W. bank of river, (— AB), 26 May 1984, O’ Callaghan, Fellingham & van Wyk 234 ( NBG) ; George , (— AB), 29 Nov 1936, Lynes 1064 ( BM) . 3423 (Knysna): Coney Glen, Knysna , (— AA), 11 Jul 1946, Levyns 7860 ( BOL) ; between Knysna Heads and Sparrebosch , 13 Jul 1946, Levyns 7870 ( BOL) , Levyns 7880 ( BOL) ; Knysna , cliffs between Noetsie and Heads, (— AA), July 1946, Levyns 7860 ( BOL) ; Noetsie River near mouth, W. side of river, above parking area of beach, (— AA), 22 May 1984, O’ Callaghan, van Wyk & Fellingham 72 ( NBG, WAG) ; Harkerville , (— AA), Sep 1998, Baard 253 ( PRE) , Baard 266 ( PRE) ; Knysna area, S.W. side of road heading to Brenton-on-Sea, directly across road from viewpoint for Knysna rivier, (— AA), 15 May 2016, Elliott & Betz TE 2016_069 ( BOL) , Elliott & Betz TE 2016_070 ( BOL) , Elliott & Betz TE 2016_071 ( BOL) , Elliott & Betz TE 2016_072 ( BOL) ; E. side of road to Noetzie Castles, along Hornlee Rd. , ca. 2 km from turn-off to N2, (— AA), 10 Nov 2017, Elliott & Betz TE 2016_271 ( BOL) , Elliott & Betz TE 2016_272 ( BOL) .

Figures

Fig. 4. Examples of plants from four species of the S.cuspidatus and allies group found in Southern Africa, showing the corresponding inflorescences beneath each plant: A and E—S. cuspidatus; B and F—S.graciliculmis; C and G—S.riparius; and D and H—S.australis. The black scale bar adjacent to the inflorescence in H represents 10 mm.

Fig. 5. Examples of spikelets from nine species of the S. cuspidatus and allies group found in Southern Africa:A—S. brunnescens; B—S. compactus; C—S. crassus; D—S.loreus; E—S. gal- pinii; F—S.cuspidatus; G—S.graciliculmis; H—S.riparius; and I—S.australis. The black scale bar represents 1 mm.

Fig. 6. Examples of nutlets from nine species of the S.cuspidatus and allies group found in Southern Africa:A—S. brunnescens; B—S. compactus; C—S. crassus; D—S. loreus; E—S. galpinii; F—S.cuspidatus; G—S.graciliculmis; H—S.riparius; and I—S.australis. The black scale bar represents 1 mm.

Fig. 14. Documented locations of S.graciliculmis.

Fig. 3. Examples of plants from five species of the S. cuspidatus and allies group found in Southern Africa, showing the corresponding inflorescences beneath each plant: A and F—S. brunnescens; B and G—S.compactus; C and H—S.crassus; D and I—S.loreus; and E and J—S.galpinii. The black scale bar adjacent to the inflorescence in J represents 10 mm.