Australian Tropical Rainforest Plants - Online edition

Urochloa subquadripara (Trin.) R.D.Webster


Webster, R.D. (1987) The Australian Paniceae (Poaceae) : 252.

Common name

Signal Grass


Annual; mat forming and rooting at the nodes. Culms prostrate, 10-50 cm long.


Leaf sheaths loose, glabrous or with tubercle-based hairs or ciliate margins; leaf blades lanceolate or linear-lanceolate, 4-15 × 0.4-1 cm, glabrous or pubescent, base subrounded, margins thicker and scabrous, apex acute or acuminate. Ligule a fimbriated membrane, few long hairs on shoulders


Inflorescence composed of 3-5 racemes borne along a central axis; unilateral, 2-6 cm long. Central inflorescence axis 3-10 cm long. Rhachis narrowly winged, glabrous on margins, with very short scabrous hairs. Spikelet packing adaxial, regular, 2 -rowed. Spikelets solitary. Fertile spikelets sessile, comprising of a basal sterile floret and a fertile floret; without rhachilla extension. Spikelets elliptic, slightly dorsally compressed, acute, 3.3-3.7 mm long; falling entire. Rhachilla internodes elongated between glumes. Glumes dissimilar and reaching apex of florets, thinner than fertile lemma. Lower glume ovate and clasping, 0.33-0.5 length of spikelet, membranous, without keels, 5-7 -veined. Lower glume with obtuse apex. Upper glume oblong; same length than spikelet, membranous, without keels, 5-7 -veined. Upper glume apex acute. Basal sterile florets barren, with palea. Lemma of lower sterile floret similar to upper glume, oblong, equal length of spikelet, membranous, 5 -veined, acute. Fertile lemma elliptic, 3-3.5 mm long, indurate. Lemma surface rugulose, margins involute, lemma apex acute. Palea involute, indurate, surface rugose.


Testa glossy, with dense low papillae.


Features not available.

Distribution and Ecology

Occurs in WA, NT, CYP, NEQ, CEQ and widespread through much of Australia. Altitudinal range from near sea level to 1150 m. Grows in sandy soils in disturbed places, along roads and railway lines in Eucalypt forest, dune forest, various types of woodland and shrubland. Also from Africa, China, India, Indo-China, Malesia, North America, South America and Papuasia.

Natural History & Notes

A troublesome weed of gardens and agriculture.

Brachiaria subquadripara (Trin.) Hitchc., Lingnan Science Journal 7: 214(1929). Panicum subquadriparum Trin., De Graminibus Paniceis : 14(1826).
RFK Code
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