Common name
Scrub Pigeon Grass

Derivation
Setaria P.Beauv., Ess. Agrostogr. 51 (1812), nom. cons.; from the Latin seta (a bristle), alluding to bristly inflorescences.

australiensis- from Australia.

Published in
Contr. New South Wales Natl. Herb. 1: 335 (1950).

Habit
Perennial, tufted. Rhizomes short. Culms erect, 60–210 cm tall, 3–6 mm diam., 6-noded. Mid-culm internodes elliptical in section. Mid-culm nodes black, glabrous. Lateral branches simple or sparsely branched. Leaf-sheaths outer margin glabrous or hairy. Ligule a fringe of hairs, 2–3 mm long. Leaf-blades lanceolate, flat, 10–35 cm long, 5–23 mm wide. Leaf-blade midrib prominent beneath. Leaf-blade surface scaberulous or scabrous, glabrous or hairy. Leaf-blade margins cartilaginous, scabrous. Leaf-blade apex acuminate.

Inflorescence
Inflorescence solid, a panicle. Peduncle antrorsely scabrous above. Panicle contracted, linear or lanceolate, 6–20 cm long, 1.5–2 cm wide. Primary panicle branches appressed or ascending, 1–2.2 cm long, sterile at the tips. Panicle axis pubescent and pilose. Panicle branches scabrous, glabrous or pubescent.

Spikelets
Spikelets subtended by an involucre. Involucre composed of bristles. Involucral bristles persistent, 1–3 per spikelet, 8–20 mm long, antrorsely scaberulous, glabrous. Pedicels reduced to a stump, tip cupuliform. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret male, upper fertile, without rhachilla extension, elliptic or ovate, dorsally compressed, gibbous, acute, 3–4 mm long, falling entire.

Glumes
Glumes thinner than fertile lemma. Lower glume ovate, 1.5–1.9 mm long, 33–50% of length of spikelet, membranous, 3–5-nerved. Lower glume apex acute. Upper glume ovate, 2.5–3.1 mm long, 75–90% of length of spikelet, membranous, 7–11-nerved. Upper glume apex acute.

Florets
Basal sterile floret 1, with palea. Lemma of lower sterile floret elliptic, 3–3.9 mm long, 100% of length of spikelet, membranous, 5–7-nerved, with nerves meeting and uniting at apex, glabrous, acute. Fertile lemma ovate, dorsally compressed, gibbous, 3–4 mm long, indurate, yellow. Lemma surface rugose. Lemma margins involute. Lemma apex acute, mucronate. Palea involute, indurate. Palea surface rugose. Anthers 3, 1–1.5 mm long. Grain with adherent pericarp, ellipsoid, 2.25 mm long. Embryo 50% of length of grain. Hilum punctiform.

Continental Distribution:
Australasia.

Australian Distribution:
Northern Territory, Queensland, New South Wales.

Northern Territory: Darwin & Gulf. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Wide Bay, Darling Downs, Moreton, Mitchell, Maranoa. New South Wales: North Coast, Northern Tablelands.

Classification. (GPWG 2001):
Panicoideae: Paniceae

Notes
Native. In tropical heaths, Brigalow forests, tropical and subtropical sub-humid woodlands, and semi-arid shrub woodlands. Flowers Mar.–Sept.