Schoenus complanatus (Levyns) T.L.Elliott & Muasya

Elliott, T. L. & Muasya, A. M., 2020, A taxonomic revision of the Epischoenus group of Schoenus (Cyperaceae, tribe Schoeneae), South African Journal of Botany 135, pp. 296-316 : 304-305

2. Schoenus complanatus (Levyns) T.L.Elliott & Muasya , S. African J. Bot. 112: 359 — 360 (2017).

Epischoenus complanatus Levyns , J.S. African Bot. 25: 79 — 80 (1959).

Type: South Africa, Western Cape Province, 3319 (Worcester): Upper Wellington Sneeuwkop , (‒CD), 11 Nov 1956, Esterhuysen 26,496 ( BOL, holo! [ BOL139410 ]; BOL! [ BOL139409 , BOL150260 ], E [ E00200179 ] — image!, L [ L0052597 ] — image!, K [ K000244900 ] — image!, M [ M0107111 ] — image!, MO [ MO-1515507 ] — image!, PRE! [ PRE0240876-0 ], S [ S-G-6798 ] — image!, iso.) . [Note: Three type specimens of E. complanatus are stored at BOL—the herbarium where Levyns worked. Of these, only one (BOL139410) has a sticker with ‘Type’ written on it; thus, we believe that Levyns designated that specimen the holotype for this species.].

Caespitose, perennial graminoid, usually phyllopodic, laterally compressed leaves (i.e. flat) and culms ( Fig. 3B and 3G ). Culms flat and wide, (163 —)255 — 389(‒555) £ (0.7 —)1.5 — 2.0(‒3.0) mm. Leaves often present, (75 —)170 — 290(‒363) £ (1.1 —)2.6‒4.0(‒6.4) mm, flattened, basal, arising from separate shoots from culms, ranging from less than half to nearly the full height of culms. Sheaths dark red at base, longitudinally striate, open, central vein terminating in a mucro up to several mm long, chartaceous (i.e. thin and paper like). Ligule absent. In fl orescence a pseudolateral panicle, dense, (12 —)22‒30(‒ 43) £ (3.0 —)4.6‒6.0(‒9.0) mm, proximal rachis length (1.3 —)6.4‒10.0 (‒14.0) mm, 2 — 3 dominant primary inflorescence bracts, erect, appressed to central axis and spikes ( Figs. 3G and 7B ). Proximal primary in fl orescence bracts (22 —)35‒45(‒64) mm long, with lateral membranaceous (chartaceous) extensions, partially involute, wide at base, firm, apex acute to obtuse, exceeding length of inflorescence slightly. Spikes 1‒3 (usually 2), (8 —)14‒20(‒28) mm long, aggregated into dense clusters along rachis, partially overlapping. Spikelets linear-lanceolate to lanceolate, 1 — 4 (usually 3) spikelets per spike, (6.7 —)8.0‒10.2(‒12.7) £ (0.9 —)1.4‒1.6(‒2.2) mm, pedicellate, usually light reddish-brown in colour and chartaceous in texture, sometimes almost completely concealed by primary inflorescence bracts, varying number of sterile glumes at base ( Fig. 8B ). Proximal spikelet prophyll absent. Rachilla relatively thick and flattened, (0.8‒)1.9‒3.4(‒ 6.0) mm long. Glumes 3‒9 per spikelet, usually chartaceous (especially lower glumes), proximal glume varying in length, (1.2‒)3.3‒5.8 (‒12.6) mm long, subproximal glume (2.0‒)3.2‒8.6(‒13.4) mm long, upper glumes longer than basal ones, apex acute to obtuse. Glume mucros often absent, short if present, proximal mucro 0‒0.2(‒0.7) mm long, subproximal mucro 0‒0.8 mm long. Stamens 2‒6 (usually 3) per floret, anthers not observed. Stigmas 3-branched, vestigial stigmas present. Perianth bristles absent (i.e. yet to be observed). Suprafloral axis sometimes thickening and strengthening, eventually curving. Nutlet (2.1‒)2.4‒3.2(‒3.5) £ (0.8‒)1.2‒1.5 (‒1.8) mm, broad elliptic, trigonous, shiny, yellowish in colour when young and turning dark reddish black with maturity, disk at base staying yellow with maturity; nutlet beak short, 0.1‒ 0.2 mm ( Fig. 10B ). ( Figs. 3 , 7 , 8 and 10 )

Flowering: Flowering specimens have been collected every month except for July.

Distribution and ecology: This species is endemic to the western mountains of the Western Cape Province of South Africa, ranging from the Groot Winterhoek Mountains in the north to the Kogelberg area in the south ( Fig. 12 ). Most specimens have been collected from high mountain locations ranging from 540‒1850 m, often growing in damp sites.

Diagnosis: The distinctly flattened culms and leaves of S. complanatus make it easily distinguishable from all other southern African Schoeneae species. Schoenus complanatus and S. selinae appear to be the two species in this group that have leaves arising from separate shoots at the base of the plants. Our observations suggest that these leaves are usually present in plants growing in post-fire habitats (see Fig. 5 )—a phenomenon also noted by Levyns (1947).

Additional collections examined

South Africa. WESTERN CAPE: 3318 (Cape Town): Stellenbosch Dist. , Simonsberg, (‒DD), 13 Apr 1975, Esterhuysen 33,808 ( BOL) . 3319 (Worcester): Great Winterhoek Mts. , (‒AA), 31 Dec 1951, Esterhuysen 19,781 ( BOL) ; Great Winterhoek , (‒AA), 27 Jan 1957, Esterhuysen 26,989 ( BOL) ; Mosterts Hoek Twins , (‒AD), 4 Sep 1955, Esterhuysen 24,267 ( BOL) ; Upper Wellington Sneeuwkop, Witte River , (‒CA), Apr 1934, Esterhuysen 24,366 ( BOL) ; Lower Wellington Sneeuwkop , ledges on S side, (‒CA), 23 Dec 1945, Esterhuysen 12,438 (BOL, NBG, PRE, SAM); Slanghoek Needle, (‒CA), 19 Nov 1950, Esterhuysen 17,776 ( BOL) ; Witteberg , (‒CA), 3 Sep 1958, Esterhuysen 27,610 ( BOL) ; Du Toit's Peak , (‒CA), 3 Apr 2006, Verboom 1077 ( BOL) ; Du Toit's Kloof Mountains , plateau to the S of Du Toit's Peak, (‒CA), 3 Feb 2008, Verboom 1279 ( BOL) ; Limietberg Nature Reserve, along small creak on SE-facing slope of Observation Peak , (‒CA), 1 Jun 2018, Elliott, Muasya & van Mazijk TE 2016_339 ( BOL) , Elliott, Muasya & van Mazijk TE 2016_340 ( BOL) , Elliott, Muasya & van Mazijk TE 2016_341 ( BOL) ; Chavonnesberg , (‒CB), 4 Oct 1942, Esterhuysen 8181 ( BOL) ; Fonteintjiesberg , (‒CB), 20 Oct 1963, Esterhuysen 30,415 ( BOL) ; Wemmershoek Pk. , (‒CC), 2 May 1945, Esterhuysen 11,575 ( BOL, K) ; Paardekop, Wemmershoek Mts. , (‒CC), 2 May 1945, Esterhuysen 11,593 ( BOL, PRE) . 3418 (Simonstown): Somerset Sneeukop , (‒BB), 12 Mar 1937, Stokoe 5000 ( BOL) ; Kogelberg Forest Reserve boundary E of Kogelberg Peak at head of Spinnekop neskloof, (‒BB), 21 Apr 1970, Boucher 1246 ( NBG) ; Kogelberg , NE of Harold Porter N.R., Elephant's Head, (‒BD), 8 Apr 2017, Helme 9208 ( BOL) ; Kogelberg, (‒BD), Sept 1953, Stokoe s.n. ( SAM [2 sheets]) . 3419 (Caledon): Landdroskop , (‒ AA), Apr 1934, Stokoe 2851 ( BOL) ; between Moordenaars Kop and Viljoen's Pass , (‒AA), Feb 1943, Stokoe 9116 ( BOL) ; Moordenaars Kop , Hottentots Holland Mtns. , (‒AA), Feb 1943, Stokoe s.n. ( SAM) ; Dwarsberg, Jonkershoek , (‒AA), 13 Mar 1967, Kerfoot 5739 ( NBG) ; Jonkershoek, Dwarsberg, near Disa Vlei , (‒AA), 29 Jun 1967, Kruger (NBG, PRE); Grabouw - Lebanon: Catchment 1b, (‒AA), 9 Jul 1967, Kruger 484 ( NBG) ; Rivier Zondereinde Mtns. , (‒AB), Apr 1930, Stokoe 2162 ( BOL) ; Jun 1949, Stokoe s.n. ( SAM) .

Figures

Fig. 3. Examples of plants from five species of the Epischoenus group found in southern Africa, showing the corresponding inflorescences beneath each plant: A and F—S. dregeanus; B and G—S.complanatus; C and H—S. quadrangularis; D and I—S.selinae; and E and J—S.rigidus. The black scale bar adjacent to the inflorescence in L represents 10 mm.

Fig. 7. Diagrammatic representations of the inflorescences of 11 species in the Epischoenus group, with spikelets illustrated in dark grey, primary inflorescence bracts in white and chartaceous (membranaceous) lateral extensions of the primary inflorescence bracts in light grey. Illustrations are not drawn to exact scale and stippling represents hairs. Inflorescences of the following species are shown: A—S. dregeanus; B—S. complanatus; C—S. quadrangularis; D—S. selinae; E—S. rigidus; F—S. crinitus; G—S. adnatus; H—S. gracillimus; I—S. schonlandii; J—S. lucidus; and K—S.neovillosus.

Fig. 8. Examples of spikelets from 11 species of the Epischoenus group found in southern Africa: A—S.dregeanus; B—S.complanatus; C—S. quadrangularis; D—S. selinae; E—S.rigidus; F—S.crinitus; G—S.adnatus; H—S.gracillimus; I—S.schonlandii; J—S.lucidus; and K—S.neovillosus. The black scale bar beside K represents 1 mm.

Fig. 10. Examples of nutlets from 11 species of the Epischoenus group found in southern Africa: A—S. dregeanus; B—S.complanatus; C—S. quadrangularis; D—S. selinae; E—S.rigidus; F—S.crinitus; G—S.adnatus; H—S.gracillimus; I—S.schonlandii; J—S.lucidus; and K—S.neovillosus. The black scale bar beside K represents 1 mm. Fully formed, mature nutlets of S.crinitus and S. neovillosus have yet to be observed.

Fig. 12. Documented locations of S.complanatus.

Fig. 5. Two specimens of S. selinae sampled from the same location 22 months apart showing the presence (A) and absence (B) of leaves arising from separate shoots than the peduncles. Specimen A (Elliott, Muasya & Muthaphuli TE2016_228) collected in July 2017 shows the presence of flat leaves on a young plant. When the same population was revisited in May 2019, plants were leafless (B—Elliott & Muasya TE2016_431), suggesting that leaves are present in only young post-fire plants of this species.