Derivation
Echinochloa P.Beauv., Ess. Agrostogr. 53 (1812); from the Greek echinos (hedgehog) and chloe (grass), alluding to the echinate inflorescence branches.

macrandra- from the Greek makros (large) and aner (man). Anthers long.

Published in
Telopea 2: 27 (1980).

Habit
Annual. Stolons absent. Culms erect, 70–200 cm tall, 3–6 mm diam., 6–8-noded. Mid-culm internodes terete, striate, smooth, glabrous. Mid-culm nodes glabrous. Lateral branches simple or sparsely branched. Leaf-sheaths loose, mostly shorter than adjacent culm internode, striately nerved, smooth, glabrous on surface. Leaf-sheaths outer margin glabrous or hairy. Ligule a fringe of hairs, 1–1.5 mm long. Collar pubescent. Leaf-blades 12–40 cm long, 4–14 mm wide. Leaf-blade midrib conspicuous. Leaf-blade venation with 12 secondary nerves. Leaf-blade surface smooth or scaberulous or scabrous, glabrous. Leaf-blade margins cartilaginous, scabrous, glabrous or tuberculate-ciliate, hairy at base. Leaf-blade apex acuminate or attenuate.

Inflorescence
Inflorescence compound, a panicle of racemes, exserted. Racemes numerous, erect or ascending, unilateral, 3–7 cm long, simple or with branchlets at base of longer racemes. Central inflorescence axis 11–25 cm long, hairy. Rhachis angular, scabrous on margins. Spikelet packing lax, 4-rowed. Raceme-bases hirsute.

Spikelets
Spikelets clustered at each node or in pairs, subequal. Pedicels unequal, 0.5–1 mm long, scabrous, tip discoid. Fertile spikelets 2-flowered, comprising 1 fertile floret, lower floret male, upper fertile, without rhachilla extension, elliptic, dorsally compressed, cuspidate, 4.8–6 mm long, 1.7–2.4 mm wide, falling entire. Rhachilla internodes elongated between glumes.

Glumes
Glumes dissimilar, thinner than fertile lemma. Lower glume ovate, clasping, 2.2–3.1 mm long, 50–66% of length of spikelet, hyaline or membranous, 5–7-nerved. Lower glume surface asperulous. Lower glume apex acute or acuminate, muticous or mucronate. Upper glume elliptic, dorsally convex in profile, 4.6–5.7 mm long, 100% of length of spikelet, membranous, 5–7-nerved. Upper glume surface scabrous, rough on nerves. Upper glume apex acuminate or caudate, muticous or awned. Upper glume awn 5–10 mm long.

Florets
Basal sterile floret 1, with palea. Lemma of lower sterile floret similar to upper glume, elliptic, 4.6–5.7 mm long, 100% of length of spikelet, membranous, 7-nerved, flat across back or concave across back, scabrous or spinulose, rough on nerves, acuminate, awned. Awn of lower sterile floret 20–90 mm long. Palea of lower sterile floret 100% of length of lemma. Fertile lemma elliptic, gibbous, 4.5–5.3 mm long, cartilaginous or indurate, much thinner above, of similar consistency on margins, yellow, glossy, 5-nerved. Lemma lateral nerves obscure. Lemma surface striate. Lemma margins involute. Lemma apex acute or cuspidate, scabrous, mucronate. Palea reflexed at apex, 100% of length of lemma, indurate. Anthers 3, 2.5–2.8 mm long, orange. Grain with adherent pericarp, ellipsoid or oblong, 3–3.1 mm long, pallid or light brown. Embryo 60% of length of grain.

Continental Distribution:
Australasia.

Australian Distribution:
Western Australia, Northern Territory.

Western Australia: Gardner, Fitzgerald. Northern Territory: Victoria River.

Classification. (GPWG 2001):
Panicoideae

Notes
Native. Restricted to the swamps near the Kimberley region of W.A. and Victoria River region N.T. Flowers Mar.–Apr.