Common name
Diel's Pigeon Grass

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

dielsii- in honour of Friedrich Ludwig Emil Diels (1874–1945). German botanist.

Published in
Beitr. Biol. Pflanzen. 10: 52 (1910).

Habit
Annual. Stolons absent or present. Culms erect or geniculately ascending or decumbent, 40–80 cm tall, 3–6-noded. Mid-culm nodes glabrous. Leaf-sheaths glabrous on surface. Leaf-sheaths outer margin glabrous. Ligule a fringe of hairs, 0.5–1.3 mm long. Leaf-blades flat, 5–28 cm long, 3.5–11 mm wide. Leaf-blade surface scabrous, glabrous.

Inflorescence
Inflorescence compound, a panicle. Panicle open, lanceolate, 2.5–17 cm long, contracted about primary branches. Primary panicle branches ascending or spreading, 0.7–3.5 cm long, bearing 7–15 fertile spikelets on each lower branch, bearing spikelets almost to the base, sterile at the tips. Panicle axis scabrous. Panicle branches scabrous.

Spikelets
Spikelets solitary. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret sterile, upper fertile, without rhachilla extension, elliptic, dorsally compressed, 2.1–2.8 mm long, 1–1.3 mm wide, falling entire.

Glumes
Glumes thinner than fertile lemma. Lower glume ovate, 1–1.9 mm long, 50–66% of length of spikelet, membranous, 3-nerved. Lower glume apex acute. Upper glume elliptic, 2.1–2.8 mm long, 90–100% of length of spikelet, membranous, 7–9-nerved. Upper glume apex obtuse.

Florets
Basal sterile floret 1, without significant palea. Lemma of lower sterile floret elliptic, 2.1–2.8 mm long, 100% of length of spikelet, membranous, 5–7-nerved, with nerves meeting and uniting at apex, glabrous, obtuse. Fertile lemma elliptic, dorsally compressed, gibbous, 2.1–2.8 mm long, indurate, yellow. Lemma surface rugose. Lemma margins involute. Lemma apex acute, mucronate. Palea involute, indurate. Palea surface rugose.

Continental Distribution:
Australasia.

Australian Distribution:
Western Australia, Northern Territory, South Australia, Queensland.

Western Australia: Hall, Dampier, Warren. Northern Territory: Central Australia North, Central Australia South. South Australia: North-western, Lake Eyre, Gairdner-Torrens Basin, Flinders Ranges, Eastern, Northern Lofty. Queensland: Cook, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Darling Downs.

Classification. (GPWG 2001):
Panicoideae: Paniceae

Notes
Native (?). In Brigalow forests, acacia shrublands, and arid hummock grasslands. Flowers sporadically throughout the year.