Schoenus quartziticus 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 : 531-532

8. Schoenus quartziticus T.L.Elliott & Muasya , sp. nov.

Type: South Africa, Western Cape Province, 3420 (Bredasdorp): Haawegskloof Farm ( Overberg Renosterveld Nature Reserve ), 500–1000 m N.W. of research centre, (–AD), 1 Oct 2016, Elliott & Muasya TE2016_127 ( BOL!, holo., MT!, NBG!, iso.) .

Caespitose, phyllopodic perennial graminoid. Culms terete, 310–678 × 0.3–0.5 mm. Leaves basal, 1–3(—6), 130–189(—273) × 0.2–1.0 mm, usually straight, proximally channelled, margin serrate above sheath. Sheaths firm, reddish-brown but paler above, longitudinally striate. Ligule usually firm but can be scarcely membranaceous, 0.2–0.8 mm long. In fl orescence a narrow pseudolateral panicle, 22–28(—47) × 3–8 mm, proximal rachis length varying in length, 7–25 mm. Proximal primary infl orescence bracts sometimes channelled proximally, apex acute to acuminate, not widened at base, (26–)37–112(—134) mm long, exceeding length of inflorescence up to several times, longitudinal veins not notable. Proximal and subproximal primary inflorescence bracts without membranaceous extensions at base. Spikes 2–4, 7.0–15.0 mm long, usually dispersed along rachis. Spikelets lanceolate, relatively short, 3.4–3.9 × 0.7–1.0 mm, pedicellate, 3–6 spikelets per spike, ranging from firm to membranaceous or chaffy in texture. Proximal spikelet prophyll 1 per spikelet, with an inconspicuous vein extending to mucro, 0.4–0.9 mm long, prophyll mucro (0.8–) 2.2–3.4 mm long. Rachilla 0.6–2.4(—7.2) mm long. Glumes 4–7 per spikelet, proximal glume (0.5–)1.0– 1.8 mm long, subproximal glume 1.0– 2.2 mm long, upper glumes longer than basal ones, lower glumes sometimes over half the length of spikelet, apex obtuse. Glume mucros absent or short, proximal mucro 0.1–1.7 mm long, subproximal mucro 0.1–1.6 mm long. Stamens 3 per floret, anthers not measured. Stigmas 3-branched, vestigial stigmas of second bisexual floret not observed. Perianth bristles about half the length of nutlet. Nutlet broad elliptic, trigonous, yellowish in colour, 1.9–2.0 × 0.6–0.7 mm. Nutlet beak, 0.4–0.8 mm long, hispid ( Figs. 2 and 4 ).

Flowering: August

Distribution and ecology: Schoenus quartziticus has been collected from the Agulhas Plain region of South Africa ( Fig. 17 ), appearing to be endemic to quartz patches on shale-derived soils.

Diagnosis: The lanceolate spikelets of S. quartziticus often have relatively thin, membranaceous glumes ( Fig. 4N ) and somewhat resemble those of the more robust form of S. exilis in size and shape. However, the nutlets of the two species differ, with those of S. quartziticus being broad elliptic, while S. exilis has narrow elliptic nutlets.

Additional collections examined

South Africa. WESTERN CAPE: 3420 (Bredasdorp): Plaatjieskraal, Farm (–AD), 7 Dec 2011, Muasya, Stirton & Curtis 6348 ( BOL) ; Haawegskloof Farm , 500 m along short-cut to reserve, W. of research centre, (–AD), 1 Oct 2016, Elliott & Muasya TE2016_124 ( BOL) , Elliott & Muasya TE2016_125 ( BOL) , Elliott & Muasya TE2016_126 ( BOL) ; Haawegskloof Farm , 500–1000 m N.W. of research centre, (–AD), 1 Oct 2016, Elliott & Muasya TE2016_127 ( BOL) ; Haawegskloof Renosterveld Reserve , (–AD), 26 Aug 2017, Muasya 7540 ( BOL) ; Haawegskloof, Farm (–AD), 26 Nov 2017, Stirton 14,441 ( BOL) ; Haarwegskloof Renosterveld Reserve , c. 200 m from entrance gate into renosterveld, c. 50–100 m from fenceline: (–AD), 30 Nov 2017, Elliott & Smith TE2016_331 ( BOL) , Elliott & Smith TE2016_332 ( BOL).

Figures

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.4. Examples of plants from six species of the Schoenus cuspidatus andallies group found in southern Africa,showing the corresponding inflorescences and spikelets beneath each plant: A,G and M—S.crassiculmis; B,H and N—S.quartziticus, C,I andO—S.limosus; D,J,and P—S.purpurascens; E,K andQ—S.prophyllus; and F,L and R—S.calceolus. 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. 17. Documented locations of Schoenus quartziticus.