Schoenus submarginalis T.L.Elliott & Muasya, 2019

Elliott, T. L., Barrett, R. L. & Muasya, A. M., 2019, A taxonomic revision of Schoenus cuspidatus and allies (Cyperaceae, tribe Schoeneae) - Part 1 *, South African Journal of Botany 121, pp. 519-535 : 530

6. Schoenus submarginalis T.L.Elliott & Muasya , sp. nov. Type: South Africa, Western Cape Province, 3321 (Ladismith): Garcia's Pass , along R323, near pull-out on W. side of highway, within 20 m of road, (– CC), 8 Jul 2017, Elliott & Muasya TE2016_215 ( BOL!, holo., MT!, NBG!, iso.).

Caespitose, phyllopodic perennial graminoid. Culms terete, slender, 208–580 × 0.2–0.8 mm. Leaves basal, 1–3, (16–)32–68(—153) × 0.2–0.9 mm, mostly straight, proximally channelled, margin usually serrate above sheath. Sheaths usually firmly clasping culm, sometimes but not always longitudinally striate. Ligule firm ( Fig. 13B ), relatively short, 0.2–1.0 mm long. In fl orescence a slender pseudolateral panicle, 11–43 × 3–8 mm, proximal rachis length 5–20 mm. Proximal primary in fl orescence bracts slender, not channelled, apex acute, never widened at base, 24–60(—84) mm long, exceeding length of inflorescence 0.5 times or more, without notable longitudinal veins. Proximal and subproximal primary inflorescence bracts never with membranaceous extensions at base. Spikes 2–14, (3.0–)7.0–16.0 mm long, sometimes overlapping. Spikelets lanceolate to slightly ovate, (2.2–)3.0–3.9(—4.1) × 1.0– 1.2 mm, pedicellate, 2–5(—8) spikelets per spike, reddish-brown with hyaline margins having adjacent small reddish-brown streaks ( Fig. 3F ). Proximal spikelet prophyll 1 per spikelet, with a raised vein extending to mucro, 0.3–1.0 mm long, prophyll mucro varying in length, 0.7–2.2(—5.2) mm long. Rachilla (0.3–)1.4–2.2(—4.0) mm long. Glumes 6–8 per spikelet, proximal glume 0.3–1.2 mm long, subproximal glume 0.6–1.4 mm long, upper glumes longer than basal ones, apex acute to acuminate, lower glumes less than half length of spikelet. Glume mucros usually relatively short, proximal mucro 0.1–0.5(—1.5) mm long, subproximal mucro 0.1–0.7 mm long. Stamens (2–)3(—4) per floret, anthers 1.3–2.5(—4.3) mm long. Stigmas 3-branched, vestigial stigmas of second bisexual floret sometimes present. Perianth bristles not observed. Nutlet broad elliptic, trigonous, yellowish in colour, 2.2–2.4 × 0.7–1.3 mm. Nutlet beak 0.3–0.6(—1.5) mm long, hispid, purplish-brown when mature ( Figs. 2 and 3 ).

Flowering: February–June

Distribution and ecology: Schoenus submarginalis is a species of mountainous regions of the Western and Eastern Cape Provinces of South Africa ( Fig. 15 ), from the slopes of the Anysberg in the west to Baviaanskloof in the east. This species tends to grow on coarse substrates at elevations over 600 m.

Diagnosis: Major diagnostic characters of Schoenus submarginalis include its relatively short (<4.2 mm) and narrow spikelets (<1.2 mm), as well as the small reddish-purple streaks adjacent to its hyaline glume margins. Schoenus exilis , S. ligulatus , and S. quartziticus also have narrow spikelets; however, these three species do not have hyaline glume margins with adjacent reddish-purple streaks and their spikelets tend to be either linear-lanceolate or narrow lanceolate, compared to the wider lanceolate spikelets of S. submarginalis . Schoenus submarginalis is most similar to S. bolusii , but the leaf sheaths of these two species differ, with S. submarginalis having firm leaf sheaths that are generally solid in colour, while S. bolusii has membranaceous leaf sheaths with reddish-purple streaks ( Fig. 13 ). In addition, S. submarginalis has on average taller culms (305–475 mm) than those of S. bolusii (249–310 mm).

Additional collections examined

South Africa. WESTERN CAPE: 3320 (Montagu): sandy vlakte on S. slopes of the Anysberg , (–AB), 21 May 1950, Esterhuysen 17,314 ( BOL, NBG) ; Langeberg, Marloth Nature Reserve, N. -facing slopes of Goedgeloof Ridge, below Misty Point , (–CD), 21 Nov 1989 , McDonald 1852 ( NBG) ; TouwsBerg, Little Karoo , (–DB), 12 Sep 1937, Levyns 6126 ( BOL) ; Touwsberg , (–DB), 18 Aug 1948, Levyns 9073 ( BOL [2 sheets]) ; Touwsberg, Farm ‘ Miskraal’, N. of Touwsberg , (–DB), 6 Oct 1993, Barker 1069 ( NBG) ; ‘ Langebergen pr. Swellendam’ , (–DD), 11 Jan 1893, Schlechter 2059 ( GRA, K, NBG, NSW) . 3321 (Ladismith): Garcia's Pass , along R323, (–CC), 8 Jul 2017, Elliott, Muasya & Muthaphuli TE 2016_215 ( BOL) , Elliott , Muasya & Muthaphuli TE 2016_217 ( BOL) ; N. side of Garcia's Pass , along R323, (–CC), 8 Jul 2017, Elliott, Muasya & Muthaphuli TE 2016_220 ( BOL) , Elliott , Muasya & Muthaphuli TE 2016_222 ( BOL) ; S. slopes of the Roodeberg , (–DA), 24 May 1950, Esterhuysen 17,151 ( BOL) ; Swartberg Pass, c. 100 m S. of road, beside a spur trail along ‘ Ou Tol’ hiking trail, (–DA), 8 May 2016, Elliott & Betz TE 2016_057 ( BOL) ; Swartberg Pass, just off of road that connects the Swartberg Pass and Prince Albert , (–DA), 8 May 2016, Elliott & Betz TE 2016_058 ( BOL) , Elliott & Betz TE 2016_060 ( BOL) . 3322 (Oudtshoorn): Swartberg Mt. slopes, (–AC), May 1926, Pocock S201 ( NBG) ; Swartberg Nature Reserve, W. side of Fonteintjie sign, (–AC), 9 Jul 2017, Elliott, Muasya & Muthaphuli TE 2016_224 ( BOL) ; Mossel Bay Div., Ruytersbosch , (–CC), 5 Dec 1951, Esterhuysen 19,434 ( BOL) . 3323 (Willowmore): Ongelegen , (–CB), Jan 1933, Fourcade ( BOL, NBG) ; Joubertina , (–DD), 5 Mar 1953, Esterhuysen 21,250 ( BOL, K) . 3324 (Steytlerville): Baviaanskloof, Enkeldoor Track , (–CB), Feb 1977, Bond 922 (K, PRE) ; Baviaanskloof N. side near Goewermentskloof (BG9), (– CB), 23 Jun 1977, Bond 1120 ( NBG, PRE) .

Figures

Fig. 13. Upper sheath and ligule of Schoenus bolusii (A) and S.submarginalis (B).The black scale bar represents 1 mm.

Fig.3. Examples of plants from six species of the Schoenus cuspidatus and allies group found in southern Africa,showing the corresponding inflorescences andspikelets beneath each plant: A, G and M—S.auritus; B, H and N—S.graminifolius; C, I and O—S. ligulatus; D,J, and P—S.exilis; E,K and Q—S.bolusii; and F, L and R—S.submarginalis. The black scale bar adjacent to the inflorescences in G—L represents 10 mm, while the scale bars adjacent to the spikelets in M—R represent 1 mm.

Fig.2. Examples of nutlets from 11 species of the Schoenus cuspidatus and allies group found in southern Africa:A—S.auritus; B—S.graminifolius; C—S.ligulatus; D—S.exilis; E—S.bolusii; F— S.submarginalis; G—S.crassiculmis; H—S.quartziticus; I—S.limosus; J—S.purpurascens; and K—S.calceolus (immature).The black scale bar represents 1 mm.The mature fruits of S.calceolus and S.prophyllus are unknown.

Fig. 15. Documented locations of Schoenus submarginalis.