Echinochloa elliptica

Echinochloa elliptica P.W. Michael & J.W. Vickery. Telopea 2: 28 (1980).

Classification. (GPWG 2001) : Subfamily Panicoideae. Paniceae.

Type of Basionym or Protologue Information: Australia: Northern Territory: Coastal Plains Research Station, 30 mi SE of Darwin, common on heavy soil banks of rice bays, tufted erect perrenial 3–4 ft high, 13 Mar 1963, M. Lazarides 6805 (HT: CANB-135762; IT: K, NT-22337).

Key references (books and floras): [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia.

Habit. Annual. Rhizomes absent. Stolons absent. Culms erect or geniculately ascending, 50–150 cm tall, compressible, 4–7 -noded. Mid-culm nodes glabrous. Lateral branches simple or sparsely branched. Leaf-sheaths hairy. Ligule a fringe of hairs, 0.3–1 mm long. Leaf-blades 7–50 cm long, 5–15 mm wide. Leaf-blade surface smooth, indumented.

Inflorescence. Inflorescence compound, a panicle of racemes. Racemes numerous, erect or ascending, 2–4 cm long. Central inflorescence axis 6–26 cm long.

Spikelets. Spikelets pedicelled. Fertile spikelets 2-flowered, the lower floret barren (rarely male), the upper fertile, comprising 1 basal sterile florets, comprising 1 fertile floret(s), without rachilla extension, elliptic, dorsally compressed, 4–4.9 mm long. Rhachilla internodes brief up to lowest fertile floret.

Glumes. Glumes dissimilar, thinner than fertile lemma. Lower glume ovate, membranous, without keels, 3–5 -nerved. Lower glume surface indumented. Lower glume apex mucronate or awned. Upper glume elliptic, 4.1–4.9 mm long, membranous, without keels, 5–7 -nerved. Upper glume surface scabrous, indumented. Upper glume apex muticous or awned. Florets. Basal sterile florets 1, barren, with palea. Lemma of lower sterile floret 100 % of length of spikelet, membranous, 5(–7) -nerved, awned.

Fertile lemma 3–4.5 mm long, without keel, 5 -nerved. Lemma apex mucronate. Anthers 3. Grain 1.9–2.3 mm long.

Continental Distribution: Australasia.

Australian Distribution: Western Australia, Northern Territory, Queensland.

Western Australia: Gardner. Northern Territory: Darwin & Gulf, Victoria River, Barkly Tableland. Queensland: Cook, Burke.

Notes. Similar taxa include E. stagnina and E. turneriana. Diagnostic features include the presence of a ligule, awned spikelets, and spikelet shape.

Native. Restricted to the Kimberley region of W.A. and in the N.T. In tropical and subtropical sub-humid woodlands, arid and semi-arid low woodlands, arid tussock grasslands, and coastal grasslands. Commonly a weed in rice fields. Flowers probably throughout the year.

AVH 2011 


Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith