Aira elegantissima Schur, Verh. Mitth. Siebenbürg. Vereins. Naturwiss. Hermannstadt 4: 85 (1853).

Aira capillartis Host, non Savi;
A. elegans Willd. ex Gaudich., Agrost. Helv. 1: 130, 355 (1811), nom. illeg.

Illustrated in: Jessop & Toelken, eds., Fl. S. Australia 4: 1906 (1986).

Vegetative form. Annual, slender, erect or decumbent, culms solitary or caespitose. Leaves mostly basal. Culms 13-56 cm high, branched above or unbranched above, 4-5 noded. Mid-culm nodes glabrous, exposed, pigmented or not pigmented, constricted. Mid-culm internodes hollow, scabrous (immediately below node, otherwise glabrous), terete. Young shoots intravaginal. Leaves non-auriculate. Basal leaf sheaths not keeled, terete, minutely scabrous (the hairs retrorse, mainly on the veins), the same colour as the lamina or purple, with the veins equally striate, with margins free, hyaline, smooth. Ligule 3.5-6.2 mm long, not lobed, decurrent, hyaline, smooth, acute, entire, abaxially glabrous or hairy (sparsely scabrid). Collar scabrous. Distinct callus at blade-sheath junction absent. Leaf blades joining the sheath gradually, flat or folded, linear, 30-80 mm long, 0.3-1.3 mm wide; adaxially scabrous to adaxially puberulous, shallowly grooved; abaxially scabrous, with the veins equally striate; with margins scabrous, apices abruptly pointed or apices blunt and rounded, hooded. Prophyll to 17 mm long, scabrous.

Reproductive organization. Plants bisexual. Rudimentary spikelets at the base of the inflorescence (on the lower branches), or absent. Incomplete spikelets absent. Hermaphrodite florets protandrous.

Inflorescence. Inflorescence a panicle, purple or silvery, erect, open, symmetrical, fully exserted. Main inflorescence axis 90-320 mm long. Peduncles 60-200 mm long, slightly scabrous, slightly ridged. Rachides 30-130 mm long, subterete, glabrous or scabrous (hairs sparse). Rachis angles glabrous. Pulvini present. Primary inflorescence branches scabrous; paired, not branched at the base, spreading, filiform, distichous, without spikelets inserted at the base. Spikelets 2 on a typical ultimate inflorescence branch, on third order branches, erect, spreading.

Hermaphrodite (`perfect') spikelets. Hermaphrodite spikelets pedicellate, 1.8-2.3 mm long, c. 2.1 mm wide, laterally compressed, oblong, not disarticulating as a separate unit, disarticulating above the glumes. Pedicels 2.3-9.2 mm long (1-5 times the spikelet length), erect, slender, sparsely scabrous, straight. Glumes two per spikelet, similar, subequal, exceeding the florets, longer than the proximal lemma. Lower glume narrowly ovate, 1.8-2.1 mm long, 0.4-0.6 mm wide, membranous, weakly keeled, acute, entire, muticous, margin scabrous (more serrate ?); 1 veined, midvein scaberulous (towards apex); intercostal regions glabrous (slightly pigmented). Upper glume narrowly ovate, 2-2.4 mm long, 0.3-0.4 mm wide, membranous, weakly keeled, acute, entire, muticous, margin scabrous (more serrate); 1 veined, midvein scaberulous (towards apex); intercostal regions glabrous (pigmented). Rudimentary florets absent. Incomplete florets absent. Hermaphrodite florets 2 per spikelet (dissimilar). Rachilla disarticulating between the florets, disarticulating directly below the florets, straight, segments 0.08-0.1 mm long, glabrous, shortly elongated between the upper glume and first floret and elongated between all florets, apically prolonged; prolongation 0.05 mm long, naked. Callus present, blunt, 0.025 mm long, silky (a tuft on each side, but on upper floret across the face of the lemma, the hairs straight, white and silky), hairs to 0.2 mm long. Lemma similar in firmness to the glumes (lower lemma 2/3s the length of the glume), laterally compressed, narrowly ovate, 1.4-1.5 mm long (upper lemma 1.6 mm), 0.25-0.3 mm wide, membranous, not keeled, acute (in upper floret c. acuminate, long & tapering to 2 short setae), entire (but bifid in upper floret); lower floret muticous and awned (upper floret). Lemma margins ciliolate (?). Lemma 5 veined. Lemma veins not confluent apically, obscure, scaberulous, with the hairs on the midvein, with the hairs only at the vein apex; intercostal regions scaberulous, the hairs only at the apex. Awns 1 (of upper floret), median. Median awn much longer than the body of the lemmas, 2.6-3 mm long, 1 veined, terete (sub-), dorsal, arising from the lower half of the lemma (1/4-1/3 from base), geniculate, column twisted, scabrous. Palea fully developed, slightly shorter than the lemmas (2/3s the length of upper floret), similar in texture to the lemmas, gaping, narrowly ovate, 1.1-1.3 mm long, 0.2-0.3 mm wide, membranous, 2-keeled, keels wingless, acute to obtuse, bidentate, margin smooth; 2 veined, veins glabrous; intercostal regions papillose. Lodicules 2, free, hyaline, oblong, acute, smooth, with entire margins, glabrous. Stamens 3. Anthers 0.4 mm long, yellow or purple, basally 2-lobed (c. 1/3 the anther length). Ovary elliptic, glabrous. Styles 2, apical, free to their bases.

Fruit. Fruit adhering to lemma and adhering to palea, elliptical to ovoid, ventrally compressed, 0.95 mm long, 0.3 mm wide, not grooved, glabrous, without a fleshy apex. Hilum 0.1 mm long, punctiform, above the base. Embryo 0.2-0.3 mm long, not waisted, with an epiblast; endosperm soft.

Cytology. 2n = 14 (European).

Common name. Delicate Hairgrass.

Distribution. Introduced. Tasmania, New South Wales, Australian Capital Territory, Victoria, Western Australia, and South Australia. World distribution: Western Eurasia, USSR and Mediterranean.

Ecology. Mesophytic; in open habitats. Grows in pasture, disturbed grassland or open woodland. Flowers Nov.-March ?. Fruits ?-March.

Vouchers. Specimens examined morphologically: N.S.W.: Mullions Ck-Dingo Dell area, 7 Dec. 1960, N.T.Burbidge 6899 (CANB). A.C.T.: Fairlight Station, damp ground on slope near creek, 15 Nov. 1959, N.T.Burbidge 6569 (CANB). Vic.: Warby Ranges State Park, 10 Nov. 1985, A.C.Beauglehole 81599 & N.E. F.N.C. (CANB!, MEL). Tas.: Proctors Rd, Hobart, 17 Dec. 1946, W.M.Curtis (HO).

Notes. Economic importance: none.

Classification. Pooideae; Poodae; Aveneae.

References. Morphology: Jacobs & Hastings, Fl. New South Wales ms. 172 (1992). Cytology: Tutin, ed., Fl. Europaea 5: 228 (1980).

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