Scleria tricristata Meganck & Bauters, 2015

Bauters, Kenneth, Meganck, Kenny, Vollesen, Kaj, Goetghebeur, Paul & Larridon, Isabel, 2015, Scleria pantadenia and Scleria tricristata: Two new species of Scleria subgenus Hypoporum (Cyperaceae, Cyperoideae, Sclerieae) from Tanzania, Phytotaxa 227 (1), pp. 45-54 : 48-50

Scleria tricristata Meganck & Bauters sp. nov. ( Fig. 2 )

Small tufted annual herb with unbranched glomerate-spicate inflorescences, composed of 6 to 14 glomerules, each containing up to seven spikelets. Scleria tricristata is unique in having ovoid to globose nutlets with a pitted surface, and the three ribs of the nutlet, three protruding, dentate ridges of translucent tissue. It resembles most closely S. delicatula in this character, but differs in the much more pronounced translucent tissue. The latter species is in general smaller than S. tricristata and has glabrous leaf sheaths.

TYPE:— TANZANIA, Sikonge District: 15 km on Ipole-Inyonga road, 1025 m elevation, 05°53’S 32°38’E, 18 May 2006, Bidgood S., Hoenselaar K., Leliyo G. & Vollesen K. 6083 (Holotype NHT!, Isotype DSM!, K!, MO!, P!).

Paratypes:— TANZANIA. Mpanda District: 55 km on Inyonga-Tabora road, 1000 m elevation, 06°18’S 32°12’E, 8 May 2006, Bidgood S., Hoenselaar K., Leliyo G. & Vollesen K. 5846 ( DSM!, K!, MO!, NHT, P!) ; Tabora District, 29 km on Tabora-Nzega road, 1100 m elevation, 04°57’S 33°02’E. 12 May 2006. Bidgood S., Hoenselaar K., Leliyo G. & Vollesen K. 5933 (K!, MO!, NHT!) .

Small, erect annual herb, growing in tufts. Roots fibrous, 0.2–0.4 mm across, purple; rhizome absent. Culms 22–40 cm long, 0.5–1 mm thick at mid height, triangular and glabrous. Leaves tristichous, slender, 10–30 cm long, 1–2 mm wide, glabrous; sheaths hairy, brown to reddish-brown coloured. Ligule absent and contraligule unpronounced. Inflorescence bracts up to 15 cm long; sheaths up to 10 cm. Inflorescence terminal, 10–20 cm long, glomerate-spicate, never branching. Glomerules 6–14 per culm, following a prophyll branching pattern, always erect, each with 3–5– (7) spikelets; glomerule bract 3.0–4.5 x 0.5–1.1 mm with mucro 1.0– 2.5 mm long. Spikelets 2.5–4 mm long, all androgynous or male; prophyll of the spikelet 0.9–1.2 mm, often with additional spikelets in its axil. Glumes 6–many, glabrous, castaneous to red, without clear midrib, spotted with red-brown dots except for the higher male glumes; lowest glume 1.4–2.0 mm long, empty, sometimes with short mucro of 0.1 mm, protruding 0.2 mm below glume tip; second glume 2.0– 2.5 mm long, female, occasionally empty; mucro 0.1–0.2 mm, protruding 0.1 mm below the glume tip; next 3–4 glumes 3.0– 3.6 mm long, spirally arranged, male, pattern as described above; higher glumes 2–many, somewhat smaller, reduced, linear, transparent, spirally arranged, male. Flowers unisexual; style trifid, dark brown, ca. 1.7 mm of which branches ca. 0.7 mm; stamens 2, filaments ca. 2.4 mm, anthers ca. 1.8 mm, scaberulous at the top. Nutlet 1.5–1.0 mm long, 1.0– 1.2 mm broad ( Fig. 3E ), ovoid to globose, surface pitted, apex short and base trigonous with small yellow-brown rim; in dried material white-greyish to pink-reddish and almost black; with three protruding, dentate ridges of yellow-transparent tissue.

Distribution and ecology:—Sikonge and Tabora districts in the Tabora region in Central Tanzania; also known from Mpanda District in West Central Tanzania. Annual growing in seasonally wet, open grasslands on sandy-loamy soils, at ca. 1100 m elevation.

Etymology:—The specific epithet tricristata refers to the crested projections on each of the three ribs of the nutlet.

Phenology:—Flowering has been observed in the field in May.

Conservation status:—Following the IUCN Red List Criteria and Categories ( IUCN 2012), Scleria tricristata should be considered as “Critical” ( CR) following the AOO criterium in GeoCAT ( Bachman et al. 2011).

Additional specimens examined— Scleria delicatula Nelmes (1955: 448) ZAMBIA. Kasama District , 10 km E of Kasama, Damp shallow soil over horizontal sandstone outcrop, 6 March 1961, E.A. Robinson 4426 ( MO) ; Chilongolwelo , Abercorn, 1400 m elevation, Very shallow soil over laterite outcrop, seasonally damp, 17 March 1961, E.A. Robinson 4535 ( MO, NY) ; Kasama District , 10 km east of Kasama, Damp shallow soil over horizontal sandstone outcrop, 26 March 1961, E.A. Robinson 4555 (K, MO, NY) ; Kasama District , 95 km E of Kasama, Deep damp, sandy soil among outcrops of laterite and sandstone, 3 April 1961, E.A. Robinson 14577 ( MO!) ; 13 km NE of Kasama, Sandy soil at edge of laterite pan, 27 April 1961, E.A. Robinson 4621 ( MO!) ; Kashashi Dambo , 55 km ESE of Mporokoso, Shallow soil over sandstone, 4 February 1962, E.A. Robinson 4920 (K, MO) ; Kashashi Dambo , 55 km ESE of Mporokoso, Black loam, seasonally damp, 4 February 1962, E.A. Robinson 4922 ( MO) ; Mporokoso District , Northern Province, Five miles North of Muzombwe , West side of Mweru-Wa-Ntipa, 16 April 1961, D.E.F. Vesey- Fitzgerald 3231 ( MO).— Scleria robinsoniana J. Raynal (1967: 239) GUINEE. On very shallow soil overhanging sandstone outcrop in seepage area, 2 September 1962, P. Adams 336 (K) ; Nyika Plateau , shady bog, 6 January 1959, E.A. Robinson 3099 (K).— Scleria sheilae J. Raynal (1967: 243) . CAMEROUN, Nkolbison, 8 km W Yaoundé, 800 m elevation, 19 November 1964, J. & A. Raynal 11970 (K) .

Figures

FIGURE 2. Scleria tricristata.—A.Habit.—B. Glomerule withseveral spikelets.—C.Detail of glume surface.—D. Nutlet.—E. Schematic overview of a glomerule.—F. Diagram of glomerule with detail of spikelet diagram. From the type specimen S. Bidgood et al. 6083 (MO). Br = spikelet bract; g = glume; p = prophyll; x = represents two stamens.t

FIGURE 3. SEM micrographs.—Scleria pantadenia (S. Bidgood et al. 5550 (MO)).—A. Nutlet.—B. Detail of nutlet surface.—C. Detail of basal tubercules.—Scleria pergracilis (E.A. Robinson 4585 (NY)).—D. Nutlet.—Scleria tricristata (S. Bidgood et al. 6083 (MO)).—E. Nutlet.—Scleria delicatula (E.A. Robinson 4555 (NY)).—F. Nutlet.