Perennials or annuals, 5-40 cm; caespitose or rhizome creeping; stem trigonous, smooth, 0.5-1 mm diam.; leaves from 1/2 to equalling stem, sheaths 10-70 mm, ligule 0; blades 10-20 cm, 1.5-4 mm wide; inflorescence a compact multiple spike, mostly 1 cluster of spikes, or up to 6 compactly together, clusters with 50-100 spikes, 5-10 mm diam., 2-5 bracts foliose, up to 20 cm; spikes 2.5-6 x 0.8-1.5 mm, caducous, with two glumes and one flower; basal part of spike axis (peduncle) enlarged, remaining on the inflorescence axis after spike falls; glumes to equalling spikes, keel smooth or scabrous or winged, sides with 2-5 nerves; flowers bisexual, stamens 2-3, stigmas 2; nut 1-4 mm, papillose or reticulate. Kyllinga is related to Cyperus subg. Mariscus in structure of the 1-flowered spikes, but in Kyllinga the inflorescences are smaller, more compact and less variable.