Cyperus castaneus Willd. APNI*
Description: Small tufted annual.
Culms trigonous, smooth, 2–10 cm high, to 1 mm diam.
Leaves not septate-nodulose, shorter than culms, to 1 mm wide. Inflorescence simple, with 1–4 branches to 3 cm long, or head-like; digitate clusters to 15 mm diam.; involucral bracts leaf-like, 1–3 usually longer than inflorescence. Spikelets flattened, 4–20 per cluster, 5–20 mm long, 1–2 mm wide in side view, to 60-flowered; rachilla not winged, persistent. Glumes emarginate, with sides 1-nerved near midrib, 1–1.4 mm long (excluding mucro to 0.8 mm long), c. 0.8 mm wide, red-brown to very dark red-brown. Stamen 1. Style 3-fid.
Nut trigonous, oblong, about two-thirds as long as glume, 0.7–1.0 mm long, c. 0.2 mm diam., red-brown to blackish.
Distribution and occurrence: Grows in open, ephemerally wet situations, on sandy soils, commonly associated with C. squarrosus L., in Callitris glaucophylla woodland; near Narrabri.
NSW subdivisions: NWS, NWP
Other Australian states: Qld S.A. N.T.
This is a variable species; the typical form occurs in N.S.W.
Text by K. L. Wilson
Taxon concept: Flora of NSW 4 (1993)
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