Tricostularia Nees

Perennial tufted herb 0.1–0.9 (–1.3) m high; plants clonal, usually forming dense tussocks 0.1–0.6 m across; rhizome thin, woody, short, branched, 0.7–2.1 mm diam., non-pseudobulbous; old leaf sheaths covering the rhizome, usually not breaking apart into fine fibres with age, pale to reddish brown; roots sand-binding. Culms slender, rigid, erect to spreading, spirally curved in T. aphylla, sometimes arcuate, not or with 1–5 nodes, terete or compressed in T. aphylla, not or finely striate, 0.3–3.3 mm diam., smooth, glabrous, green to yellow-green, base not enlarged. Leaves mostly basal, numerous, and sometimes 1–5 cauline; phyllotaxy loosely spirotristichous; sheath 9–100 mm long, 0.5–3.5 mm wide, slightly broader than the leaf lamina, glabrous except margins glabrous or scabrid, straw-coloured to dark red-brown, dull, upper margin membranous, oblique, usually finely ciliate, ligule absent; cauline sheath usually tight around culm (loose in T. sandifordiana); pseudopetiole absent, obscure or rarely distinct; basal leaves often with a much reduced lamina, not exceeding the culms, lamina dorsiventral, 0.5–12.5 cm long, 0.3–1.1 mm wide; bases white or brown-membranous, not dividing; lamina ± linear, channelled, ± flexuous, old leaf tips not curling, finely multi-striate, glabrous except for margins, green to brown, concolorous, keeled along midvein or not, sometimes with 3 primary impressed veins, margins sometimes ribbed and finely scabrous, not recurved, apex long-attenuate, setaceous; lowest leaves reduced to a sheath, lacking a lamina, pale to reddish brown. Inflorescence slender or contracted, panicle-like or subcapitate, straight to somewhat flexuous, not or with 1–9 nodes, 0.7–9.0 cm long, 3–17 mm wide, usually not interrupted, axis green or yellow-green, not glaucous; bracts reduced leaf-like, rarely almost pungent, not or exceeding the spikelet clusters in length, sheaths in the lower part of the inflorescence open, not or sometimes enveloping the higher bracts, gradually reducing along the inflorescence, basal bract somewhat shorter than or sometimes exceeding inflorescence, to 15 mm long; branches erect, with solitary or 2–7 spikelets, usually in a terminal cluster (rarely with a second distant cluster), spikelet(s) on short, terete, glabrous peduncles 0.2–4 mm long, arising in each bract axil; spikelet prophyll present, sheath 0.5–7 mm long, brown, with 1 or 3 distinct veins, partially enclosing the spikelet, with a slender lamina 0.6–2.5 mm long, brown. Spikelets brown, lanceolate to oblate, 2.8–10 mm long, terete, with 4–7(–9) glumes, only topmost 2 or 3 fertile, the lower 1 or 2 flowers male, sterile or bisexual, the upper flower bisexual, fertile, no reduced glume above the florets; glumes distichous or subdistichous, basal glume 1.4–4.5 mm long, fertile glumes 2.9–9.8 mm long, 0.7–2.8 mm wide, membranous, very pale red-brown (sometimes translucent) to very dark red-brown (apex often darker than body), often sparsely scabrous on the keel, usually ciliate on the margins, face glabrous, ovate-lanceolate, acute to acuminate or obtuse, with a mucro 0.1–1.2 mm long, keel distinct; rachilla compact and not sinuous in fruiting spikelets. Perianth segments 6 (rarely fewer), whitish, minute, 0.2–1.2 mm long, usually unequal, commonly expanded at base, tapering to a fine point. Stamens 3; anther connective 2.3–6.9 mm long, subulate; anthers yellow, pale yellow or cream, 1.4–4.6 mm long, with a glabrous apical appendage 0.15–0.9 mm long. Style trifid, base 0.5–3.5 mm long, usually glabrous, sometimes hispidulous, slender above, not or scarcely dilated below, branches 1.3–3.7 mm long, hispidulous. Nutlet shortly stipitate, stipe 0.4–0.5 mm long, somewhat constricted, obovoid to obpyriform or broad ellipsoid, obscurely trigonous, dull, mid-brown to dark brown or almost black, 1.2–2.5 mm long including the stipe and style base, 0.8–1.5 mm diam., faces smooth, usually puberulous especially near apex, sometimes hispidulous or glabrous, epidermal cells usually square–hexagonal, inconspicuous, with three fine white ribs, style base only slightly enlarged, thick, persistent, and very shortly conical or thin and cap-like; embryo not assessed, but probably Schoenus-type. Photosynthetic pathway inferred from anatomy to be C3 (based on three species assessed).