Description: Perennials or annuals with or without rhizomes.
Ligule a membrane fringed with short hairs, sometimes reduced.
Inflorescence usually narrow and spike-like. Spikelets acuminate or obtuse, glabrous, distinctly or slightly laterally compressed at the apex, usually in pairs on unequal pedicels. Glumes equal or subequal; sometimes with a thickened appendage at the apex; lower glume slightly to much shorter than the spikelet, 3–5 nerved; upper as long as the spikelet, 5–9-nerved. Lower lemna usually male, similar to upper glume, 5–7-nerved; palea thinner and slightly shorter. Upper lemna bisexual, indurated, brittle, smooth or minutely pitted, shiny, sometimes with a thickened appendage at the apex. Hilum linear, elongated.
Distribution and occurrence: A genus of c. 30 species, mostly from Arfica; 1 sp.
Widely but uncommonly planted as a pasture greass for damp areas.
From the greek words for "top" and "horn" referring to the thickened appendage sometimes present at the top of the lemna.
Text by L.J.Murray
Taxon concept: Jacobs, S.W.L., Whalley, R.D.B., Wheeler, D.J.B.(2008) Grasses of New South Wales 4th Edition.