Schoenus selinae T.L.Elliott, Muthaphuli & Muasya, 2020

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 : 307-308

4. Schoenus selinae T.L.Elliott, Muthaphuli & Muasya , sp. nov.

Type: South Africa, Western Cape Province, 3324 (Steytlerville): Baviaanskloof Mtns ., main peak to W of Bosrug , (‒CA), 27 Oct 2018, Euston-Brown 5519 ( BOL!, holo.; MT!, iso.) .

Caespitose, perennial graminoid, aphyllopodic ( Fig. 3D and 3I ). Culms with ridges (most evident on dried specimens), (160 —) 340 — 527(‒700) £ (0.3 —)0.6 — 0.8(‒1.1) mm. Leaves usually absent along culm, flat and wide leaves sometimes present in young (postfire) plants arising from separate shoots than peduncles ( Figs. 3I , 5 and 7D ). Sheaths red to reddish-black, longitudinally striate, open, central vein terminating in a mucro up to several mm long, semi-firm but often becoming chartaceous distally. Ligule absent. In fl orescence an erect pseudolateral panicle, (8 —)14‒21(‒30) £ (2.0 —)3.0‒5.5(‒9.0) mm, proximal rachis length (3.0 —)6.0‒8.0(‒9.5) mm, 2 dominant proximal inflorescence bracts appressed to the central axis and spikes ( Fig. 7D ). Proximal primary in fl orescence bracts (11 —)19‒29(‒46) mm long, wide lateral chartaceous extensions at base partially covering spikes, involute, exceeding length of inflorescence slightly, apex acute to obtuse but readily breaking-off. Spikes 1 — 2, (6 —)12‒15(‒23) mm long, clusters partially overlapping. Spikelets linear-lanceolate to lanceolate, 1 — 5 spikelets per spike, (6.4 —)7.8‒9.8(‒12.0) £ (0.6 —) 1.1‒1.5(‒2.6) mm, pedicellate, colour light reddish-brown to dark reddish-brown, texture firm and opaque, partially to almost completely concealed by lateral chartaceous extensions of primary inflorescence bracts, varying number of sterile glumes at spikelet base ( Fig. 8D ). Proximal spikelet prophyll and mucro absent. Rachilla (0.1‒)1.5‒3.4(‒6.9) mm long. Glumes 5‒12 per spikelet, texture opaque and firm, sometimes with narrow hyaline margins (more evident when glumes dark reddish-brown), lower glumes varying in length, proximal glume (0.9‒)1.6‒3.4(‒6.9) mm long, subproximal glume (0.8‒)1.7‒3.1(‒4.9) mm long, upper glumes longer than basal ones, apex acuminate to obtuse. Glume mucros often absent, proximal mucro 0‒0.6(‒2.3) mm long, subproximal mucro 0‒0.5(‒2.3) mm long. Stamens 3 per floret, anthers 2.1‒3.1(‒4.0) mm long. Stigmas 2 — 3-branched, vestigial stigmas present. Perianth bristles absent (i.e. yet to be observed). Suprafloral axis sometimes thickening and strengthening, eventually curving. Nutlet (1.7‒)2.1‒2.3(‒4.2) £ 0.7‒ 1.1(‒1.5) mm, broad elliptic, trigonous, stipitate, matted, yellowish in colour when young and turning reddish-brown with maturity; nutlet beak 0.2‒0.7 mm ( Fig. 10D ). ( Figs. 3 , 7 , 8 and 10 )

Flowering: September to May

Distribution and ecology: Schoenus selinae has a relatively wide distribution, with specimens having been collected from the Cederberg Mountains in the north, the Cape Peninsula in the west and the Humansdorp area of the Eastern Cape Province in the east ( Fig. 14 ). Although this species usually prefers wet mountainous habitats, it has also been collected from forest margins. The known elevational range of S. selinae is between approximately 150 and 1700 m.

Diagnosis: Schoenus selinae most resembles S. lucidus , S. neovillosus and S. rigidus in the Epischoenus group and Schoenus pseudoloreus (K uk ü.) T.L.Elliott & Muasya in the S. compar — S. pictus group. Similar to S. selinae , S. rigidus has inflorescence bracts with lateral chartaceous extensions; however, the inflorescence shape of S. rigidus is more branched with lateral chartaceous extensions only at base of the spikes, whereas S. selinae has primary inflorescence bracts with chartaceous extensions that extend along a greater portion of the spike length. The appression of the primary inflorescence bracts relative to the central axis of the inflorescence differs between species: S. selinae appears to have more linear inflorescences as its primary inflorescence bracts are appressed to the central axis and spikes, while the inflorescence of S. rigidus appears more branched as only the proximal primary inflorescence bract is appressed relative to the central axis of the inflorescence. The subsequent inflorescence bracts of S. rigidus are adjacent to their corresponding spikes and not appressed to the central axis ( Figs. 7D and 7E ).

Other species that could be confused with S. selinae are S. lucidus and S. neovillosus , but the lateral chartaceous extensions on the inflorescence bracts and presence of hairs differentiate these three species. Whereas S. lucidus and S. neovillosus are partially hairy on their inflorescences and/or culms, S. selinae is glabrous. In addition, the inflorescence bracts of S. lucidus and S. neovillosus do not have notable lateral chartaceous extensions, such as in S. selinae . Schoenus pseudoloreus also resembles S. selinae , but the former species has leaves along the basal part of its culms, whereas S. selinae lacks this character (although young post-fire plants can sometimes have leaves arising from separate shoots to the peduncles).

In some cases, the inflorescence of S. selinae consists of one spike that is mostly concealed by the lateral chartaceous extensions of the proximal primary inflorescence bract. This form of S. selinae most resembles that of S. pictus ( Elliott and Muasya, 2018) , but the lateral extensions of the primary inflorescence bracts of S. pictus are firmer and that species has leaves that arise from the lower part of its culms.

Additional collections examined

South Africa. EASTERN CAPE: 3323 (Willowmore): Kouga Mountains, Quaggasvlakte, S slope of main peak above Quaggasvlakte, (‒ DA), 13 Feb 2016, Euston-Brown 4515 (BOL); Joubertina, (‒DC), 24 Nov 1941, Esterhuysen 6861 (BOL, NBG, PRE); Die Hoek., N side of Zitzikamma Mts. near Joubertina, (‒DC), 6 Nov 1949, Esterhuysen 16,394 (BOL, NBG, K); 1 Nov 1957, Esterhuysen 27,308 (BOL); Formosa Pk., Zitzikamma Mts., (‒DC), 1 Dec 1957, Esterhuysen 27,392a (BOL); streamside on slopes of Kouga Pk., near Joubertina, (‒DD), 28 Oct 1949, Esterhuysen 16,286 (BOL, K, NBG). 3324 (Steytlerville): Cockscomb, Gr. Winterhoek Mts., (‒DB), 2 Feb 1958, Esterhuysen 27,538 (BOL, PRE). 3424 (Humansdorp): Witte Els Bosch, hills near coast, (‒ AA), 13 Nov 1941, Esterhuysen 6743 (BOL [2 sheets], NBG [2 sheets], SAM); Witte Els Bosch Pk., (‒AA), 16 Nov 1941, Esterhuysen 6771 (BOL); Humansdorp, (‒BB), 17 Apr 1979, de Kock 20 (NBG). WESTERN CAPE: 3218 (Clanwilliam): W slopes below Olifants River Dome, (‒ DB), 16 Apr 1949, Esterhuysen 15,295 (BOL, NBG). 3219 (Wuppertal): Cederberg Wilderness Area, along R364, Rocklands area, (‒AA), 14 Jul 2016, Elliott & Muasya TE2016_090 (BOL). 3318 (Cape Town): Devils Peak, (‒CD), 23 Feb 1943, Esterhuysen 10,043 (BOL); Table Mt., unburnt forest margin above forest on side of Skeleton Gorge, (‒CD), 3 Sep 1950, Esterhuysen 17,421 (BOL); stream bank on steep upper S slopes of Guardian Peak, (‒DD), 7 Oct 1945, Esterhuysen 11,995 (BOL); Jonkershoek, Jonkersnek, (‒DD), 29 Jun 1967, Kruger 462 (K, NBG). 3319 (Worcester): damp kloof near Skuurfberg, (‒AB), Dec 1931, Stokoe 2643 (BOL); rocky kloof on SW side of Schurfteberg Pk., (‒AB), 7 Dec 1948, Esterhuysen 14,716 (BOL [2 sheets], NBG, SAM); Michell's Pass, (‒AD), Dec 1929, Stokoe s.n. (BOL); Witels Kloof, (‒AD), 9 Oct 1956, Esterhuysen 26,329 (BOL); Waaihoek Mt., (‒CB), 15 Dec 1942, Esterhuysen 8295 (BOL); Fonteintjiesberg, (‒CB), 26 Nov 1944, Esterhuysen 10,975 (BOL [2 sheets], NBG); E of Fonteintjiesberg, (‒CB), 2 Jan 1950, Esterhuysen 16,694 (BOL, NBG); Waaihoek Peak, (‒CB), 24 Jan 1954, Esterhuysen 22,672 (BOL); Wemmershoek Mts., SE end, (‒ CC), 19 Oct 1943, Esterhuysen 9064 (BOL); Keeromsberg, (‒DA), 18 May 1944, Esterhuysen 10,156 (BOL, PRE). 3320 (Montagu): Witteberg, S side of range, roughly S of Bantams, (‒BC), 31 Jan 1961, Esterhuysen 28,862 (BOL); Witteberg, S of Bantams, (‒BC), 4 Nov 1963, Esterhuysen 30,507 (BOL, PRE); on the edge of Die Plaat where the path levels out, just to W of Koloniesbos, lower slopes of 11 O'Clock Peak, Swellendam State Forest, (‒CD), 3 Nov 1987, McDonald 1430 (NBG); Marloth Nature Reserve, ca. 1 — 1.25 km to W of Goedgeloof Hut, growing on E side of Grootrivier, (‒CD), 17 Sep 2018, Elliott & van Mazijk TE2016_405 (BOL); S slopes of the Anysberg, (‒DA), 21 May 1950, Esterhuysen 17,084 (BOL); lower S slopes of Langebergen above Strawberry Hill, (‒DD), 10 Sep 1944, Esterhuysen 10,402 (BOL); steep damp side of kloof on S slopes of Langebergen above Strawberry Hill, (‒DD), 10 Sep 1944, Esterhuysen 10,497 (BOL [2 sheets]); Boosmansbos Wilderness Area, Langeberg, high ridge above Platbosrivierskloof, (‒DD), 29 May 1986, McDonald 1158 (NBG). 3321 (Ladismith): shady kloof in Klein Swartberge, (‒AC), 20 Aug 1948, Levyns 9112 (BOL); Toverkop, Swartberg near Ladismith, (‒AC), 15 Dec 1956, Esterhuysen 26,718 (BOL). 3322 (Oudtshoorn): Swartberg Nature Reserve, along road to Gamkaskloof, c. 1 — 2 km from turn-off from Swartberg Pass road, (‒AC), 9 Jul 2017, Elliott, Muasya & Muthaphuli TE2016_228 (BOL); 9 May 2019, Elliott & Muasya TE2016_431 (BOL). 3418 (Simonstown): Kirstenbosch, slopes in Nursery Gorge, (‒AB), 6 Jan 1946, Esterhuysen 12,534 (BOL). 3419 (Caledon): Riviersonderend Mountain Catchment Area, c. 1.5 — 1.75 km to NNW of reception towers, (‒BA), 24 Oct 2018, Elliott TE2016_419 (BOL); "Pheasantshoek" near Viljoenshof, (‒DA), 15 Sep 1976, Esterhuysen 34,378 (BOL). 3421 (Riversdale): S slopes of Langeberge, (‒AB), 19 May 1950, Esterhuysen 17,013 (BOL, K). 3423 (Knysna): Noetzie, (‒AA), 14 Sep 1960, Acocks 21,521 (PRE).

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. 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.

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. 14. Documented locations of S. selinae.