sulcus (L.) = furrow or wrinkle. Refers to the striate culms.
WCM Protologue Reference:
Pillans, Trans. Roy. Soc. South Africa 29: 354 (1942)
Vegetative parts: plants mat-Forming or forming long lines of culms, 0.2–0.5 m tall, basal diameter 0.01–3 m, crown diameter 0.1–3 m, with rhizomes. Rhizome very short with culms aggregated at base or spreading, unbranched or sparsely branched, culms evenly spaced, 5–10 mm in diam., culms 1–2 mm apart. Fertile culms unbranched, distinctly hollow, striate, green, 0.2–0.5 m tall, diameter at base 1–2 mm, diameter at apex 1–2 mm. Sheaths persistent, with no abscission line, closely convoluted, 10–15 mm long, light green-brown, to brown or grey, apical margins coriaceous, like the rest of the body or narrowly membranous, hyaline shoulders small, rounded, hyaline shoulder 0.1 of sheath body length, apex, excluding the membranous lobes, obtuse. Sheath-mucro penicellate, straight and erect, 2–3 mm long. Males: male inflorescence with 2–5 spikelets, paniculate, 10–25 mm long, 5–13 mm wide. Male inflorescence spathes caducous, taller than spikelets, cartilaginous, triangular, red-brown with pale margins and distinct penicillate awn. Male flowers in spikelets. Male spikelets erect on stiff pedicels or sessile, ovate or orbicular, apex rounded or obtuse, 4–9 mm, 3–6 mm, with 20–25 flowers, pedicels absent ie spikelets sessile or shorter than the spikelets, terete or angular or flattened. Male bracts as tall as flowers or taller than flowers, 2–5 mm long, ovate, acuminate, chartaceous or cartilaginous, bract upper margin like body of bract, bract awn less than half as long as the bract body, with narrow membranous margins. Male flower 2–4 mm long. Male tepals sepals and petals the same rigidity, cartilaginous or membranous, oblong or ovate, inner tepals longer than outer tepals. Male outer lateral tepals conduplicate or keeled or winged, glabrous. Anthers 1.5–4 mm long, exserted from the flowers. Pistillode absent. Females: female inflorescence with 1 spikelet. Female spathes shorter than the spikelets or as long as the spikelets, persistent, cartilaginous. Female spikelet sessile, elliptical or obovate or obtriangular, apex truncate or acute, 18–30 mm long, with 1 flowers, with 4–12 sterile bracts. Female bracts taller than flowers, erect, 10–18 mm long, oblong or ovate, acuminate, cartilaginous, apical margin like rest of bract, paler than body of bract, awn less than half as long as the bract body. Female flower 12–14 mm long, with a fleshy pedicel. Female tepals membranous, glabrous and smooth, smaller than nut and not obscuring the nut surface, midrib flush with the tepal body, apices acute, inner whorl longer than outer or inner and outer whorls the same length. Female outer lateral tepals like other tepals, 2–5 mm long. Female odd outer tepal oblong, 2–5 mm long. Female inner tepals oblong, 3.5–5 mm long. Staminodes absent. Styles plumose, white, 2. Style bases free. Ovary with 1 locule, indehiscent. Fruit: indehiscent fruits with a hard woody ovary wall. Perianth presence on fruits persistent, membranous, shorter than nut. Nut cap smooth, wall smooth, (10.33–)12.8(–14.83) mm long, (3.33–)3.7(–3.83) mm diam., shape in side view oblong (torpedo-shaped), shape in top view round in cross section, tan. Elaiosome present, white, 2 mm long, less than half as long as nut.