Cyperus alternifolius subsp. flabelliformis Kük.

Rhizome short, stout. Stems to 60 cm high, stout, subterete. Leaves reduced to closely appressed, very pale brown basal sheaths. Involucral bracts many, ± equal, to 25 cm × 10 mm, > inflorescence, tips shortly acuminate. Inflorescence a compound umbel; rays many, to 8 cm long. Spikelets in small clusters at tips of rays, ± 4 × 2 mm, ovoid to linear-oblong, compressed, shining. Glumes densely imbricate, ± 2 mm long, ovate, obtuse, hyaline, white to light brown with green keel. Stamens 3. Style-branches 3. Nut ± ⅓ length of glume, trigonous, ovoid-ellipsoid, brown.

[From: Healy and Edgar (1980) Flora of New Zealand. Volume 3. as Cyperus involucratus Rottb.]