Avena byzantina K.Koch, Vegetative form. Annual, caespitose. Leaves mostly basal. Culms 50-100(-150) cm high, unbranched above, 3-4 noded. Mid-culm nodes glabrous, hidden by the leaf sheaths, not pigmented, constricted. Mid-culm internodes hollow, glabrous, terete. Leaves non-auriculate. Basal leaf sheaths upper part keeled, terete, glabrous, with the veins equally striate, with readily visible transverse veins, with margins free, membranous, smooth. Ligule 3-7 mm long, not lobed, decurrent, membranous, obscurely ciliolate, obtuse, erose, abaxially hairy. Collar glabrous. Distinct callus at blade-sheath junction absent. Leaf blades joining the sheath gradually, flat, linear, 170-290 mm long, 5-9(-15) mm wide; adaxially scabrous (particularly toward apex), shallowly grooved or not grooved; abaxially glabrous or abaxially scabrous (particularly toward apex), with midrib prominent or with the veins equally striate; with margins scabrous, apices abruptly pointed, hooded; convolute in bud.

Reproductive organization. Plants bisexual. Rudimentary spikelets at the base of the inflorescence, or absent. Incomplete spikelets absent. Inflorescence of cleistogamous spikelets.

Inflorescence. Inflorescence a panicle, green, nodding, open, symmetrical, fully exserted. Main inflorescence axis 335-590 mm long. Peduncles 200-380 mm long, glabrous (occasionally slightly glaucous), slightly ridged. Rachides 105-210 mm long, terete, glabrous (occasionally glaucous). Pulvini present. Primary inflorescence branches glabrous or scabrous; solitary, branching at the base, spreading, distichous. Spikelets 1-2 on a typical ultimate inflorescence branch, on second order branches to on fourth order branches, pendulous.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets pedicellate, 25-30(-35) mm long, 28 mm wide, laterally compressed, cuneate, not disarticulating as a separate unit. Pedicels 8-55 mm long, slender (distally dilated), antrorsely scabrous. Glumes two per spikelet, similar, equal in length or subequal, exceeding the florets, longer than the proximal lemma. Lower glume narrowly oblong to narrowly elliptic, 23-28 mm long, 3-4 mm wide, membranous, dorsally rounded, subulate, entire, muticous, margin smooth; (7-)9 veined, veins prominent, midvein glabrous; intercostal regions glabrous. Upper glume narrowly oblong to narrowly elliptic, 25-28 mm long, 3-4 mm wide, membranous, dorsally rounded, subulate, entire, muticous, margin smooth; (7-)9-11 veined, veins prominent, midvein glabrous; intercostal regions glabrous. Rudimentary florets distal to the hermaphrodite florets. Incomplete florets absent. Hermaphrodite florets 2-3 per spikelet. Rachilla not disarticulating between the florets (but may fracture at the base of the segment below each floret), straight, segments 2-2.2 mm long, glabrous or pubescent (hairs isolated), elongated between all florets, apically prolonged; prolongation 4.2-5 mm long, terminated by a rudimentary floret. Callus present, blunt, 0.8 mm long, glabrous or silky (hairs golden), hairs to 6 mm long. Lemma decidedly firmer than the glumes, laterally compressed, narrowly ovate to narrowly elliptic, 16-19 mm long, 3-3.5 mm wide, coriaceous, not keeled, shortly obtuse, entire (?); apex membranous; muticous and awned (upper florets unawned). Lemma margins membranous; smooth. Lemma 7 veined. Lemma veins not confluent apically, prominent (at the apex), the laterals raised and the marginals raised, connected by obscure transverse veins, glabrous; intercostal regions scaberulous or scaberulous and silky (rarely with isolated hairs), the hairs scabrid hairs only at the apex. Awns 1, median. Median awn much longer than the body of the lemmas (c. twice the lemma), 25-35 mm long, 1 veined, terete, dorsal; 8.5-12 mm below tip; arising from the mid-point of the lemma, straight, column twisted (rarely, or only slightly) or column not twisted (usually no distinction between column and bristle), scabrous. Palea fully developed, slightly shorter than the lemmas, thinner than the lemmas, narrowly elliptic, 13.6-14.5 mm long, 3-3.8 mm wide, lateral faces membranous and coriaceous (slightly), 2-keeled, keels wingless, acute, bifid, margin smooth; 2 veined, veins ciliate (hairs to 0.4 mm long, soft, straight); intercostal regions glabrous, or intercostal regions puberulous (hairs sparse). Lodicules 2, free, hyaline, ovate, acute, smooth, with entire margins, glabrous. Stamens 3. Anthers yellow, entire or shortly basally 2-lobed. Cleistogamous anthers 3.4-3.6 mm long. Ovary obovoid, silky, with the hairs over the entire ovary. Styles 2, apical, free to their bases.

Fruit. Fruit free from both lemma and palea, oblong, ventrally compressed, 8.5 mm long, 2.3-2.5 mm wide, longitudinally grooved, silky, with dense hairs, the hairs covering most of the body, with a fleshy apex. Hilum linear, at the base. Embryo 3 mm long, not waisted, with an epiblast; endosperm hard.

Distribution. Introduced.

Ecology. Mesophytic. Not recorded as naturalised. Flowers Oct.-Nov. Fruits Oct.-Nov.

Vouchers. Specimens examined morphologically: Qld: Eight Mile Plain near Brisbane, in rows between pineapples, in brown sandy loam, erect, inflorescence nodding, 2 Nov. 1930, C.E.Hubbard 4788 (CANB1, K). N.S.W.: Bla , urban area, 15 Nov. 1992, N.Lloyd 1256 (CANB). A.C.T.: Turner, Canberra, old garden bed, 31 Oct. 1957, R.Pullen 731 (CANB).

Classification. Pooideae; Poodae; Aveneae.

References. Morphology: S.W.L.Jacobs & S.M. Hastings.

Cite this publication as:
C.M. Weiller, M.J. Henwood, J. Lenz and L. Watson (1995 onwards). `Pooideae (Poaceae) in Australia - Descriptions and Illustrations'. URL http://muse.bio.cornell.edu/delta/
Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993) should also be cited.

References and Acknowledgements