Urochloa panicoides

Name and classification

Urochloa panicoides Beauv.
(=Panicum helopus Trin.)
Family Poaceae, Tribe Paniceae

Common names

liverseed grass

Disseminule

spikelet; disarticulation below glumes

Description

Spikelets of 1 fertile floret and 1 basal sterile lemma; spikelet elliptic, strongly dorsally compressed, plano-convex, apex acute; 2.5–5.5 mm long, 1.5–2.25 mm wide. Glumes membranous, glabrous, dissimilar; lower glume ca. 1/4 – 1/3 (1/2) as long as spikelet, wrapping around the base of the spikelet, 3–5-nerved; upper glume as long as spikelet, 7–13-nerved. Sterile lemma similar to upper glume, but 5–7-nerved. Fertile lemma elliptic, 2.6–3.5 mm long, 1.5–2 mm wide, indurate, surface with numerous, low transverse ridges, apex obtuse and awned, awn 0.3–1 mm long, not extending beyond tip of spikelet; lemma margins inrolled, enclosing palea. Caryopsis 2–2.5 mm long; embryo ca. 3/4 as long as caryopsis; hilum linear to narrowly obovate, 1/3 length of caryopsis.

Identification considerations

Similar species

Urochloa ramosa (L.) R.D. Webster (non-FNW)

Urochloa texana (Buckley) R.D. Webster (non-FNW)

Distribution

Africa: Botswana, Eritrea, Ethiopia, Kenya, Malawi, Mauritius, Mozambique, Namibia, Somalia, South Africa, Sudan, Swaziland, Tanzania, Uganda, Zambia, Zimbabwe; Asia: Yemen, India, Pakistan, Thailand; Australia; Argentina; United States

native to southern Africa

Habitat

woodlands, shrublands, damp places; a weed of lawns, roadsides, rotation crops, pastures.

General information

Urochloa panicoides is a tufted annual grass, to 100 cm tall. In Australia, it grows in tropical-subtropical sub-humid woodlands to semi-arid shrub woodlands. It is reported to cause nitrate poisoning in livestock.

A, spikelet in ventral view showing lower glume and sterile lemma; B, spikelet in dorsal view showing upper glume; C, floret in ventral view showing palea and margins of fertile lemma; D, floret in dorsal view showing lemma

A, spikelet in ventral view showing lower glume and sterile lemma; B, spikelet in dorsal view showing upper glume; C, floret in ventral view showing palea and margins of fertile lemma; D, floret in dorsal view showing lemma

caryopsis in ventral view showing hilum; photo by Mark Thurmond

caryopsis in ventral view showing hilum; photo by Mark Thurmond

portions of inflorescence; photo by Mark Thurmond

portions of inflorescence; photo by Mark Thurmond

A, spikelet in ventral view; B, spikelet in dorsal view; C, floret in ventral view; D, floret in dorsal view; E, caryopsis in ventral view; F, caryopsis in dorsal view; drawing by Lynda E. Chandler

A, spikelet in ventral view; B, spikelet in dorsal view; C, floret in ventral view; D, floret in dorsal view; E, caryopsis in ventral view; F, caryopsis in dorsal view; drawing by Lynda E. Chandler