Common name
Early Hairgrass

Derivation
Aira L., Sp. Pl. 63 (1753); Classical Greek name for darnel or possibly another species of Lolium. Name now applied to quite a separate genus.

praecox- Latin for early. Flowering early in the spring.

Published in
Sp. Pl. 1: 62 (1753).

Habit
Annual. Culms erect, 2–25 cm tall, 2–3-noded. Mid-culm internodes glabrous or pubescent. Leaves mostly basal or cauline. Ligule an eciliate membrane, 1.5–4.3 mm long, entire, obtuse. Leaf-blades filiform, conduplicate or involute or convolute, 0.5–5 cm long, 0.3–0.6 mm wide. Leaf-blade surface smooth or scaberulous, puberulous. Leaf-blade apex acute.

Inflorescence
Inflorescence compound, a panicle. Panicle contracted or spiciform, linear or oblong, 0.5–4.5 cm long, 0.2–0.8 cm wide. Primary panicle branches ascending or spreading.

Spikelets
Spikelets solitary. Pedicels linear, terete, 0.6–3 mm long, 30–50% of length of fertile spikelet. Fertile spikelets 2-flowered, comprising 2 fertile florets, without rhachilla extension, oblong to ovate, laterally compressed, 3–3.8 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Rhachilla internodes suppressed between florets (florets arising at about the same level). Floret callus pubescent.

Glumes
Glumes persistent, similar, thinner than fertile lemma, shiny, gaping. Lower glume ovate, 3–4 mm long, equalling upper glume, membranous, much thinner above, much thinner on margins, 1-keeled, 1–3-nerved, midnerve scaberulous. Lower glume apex acute. Upper glume ovate, 3–3.8 mm long, 110% of length of adjacent fertile lemma, membranous, 1-keeled, 1–3-nerved, midnerve scaberulous. Upper glume apex acute or acuminate.

Florets
Fertile lemma ovate, laterally compressed, lanceolate in profile, 2.5–3.5 mm long, cartilaginous, 5-nerved. Lemma lateral nerves obscure. Lemma surface smooth or scaberulous, rough above. Lemma margins involute, covering most of palea. Lemma apex dentate, 2–3-fid, acuminate,1-awned. Median (principal) awn dorsal, arising 30–40% way up back of lemma, geniculate, 3.4–4.3 mm long overall, with a twisted column. Palea elliptic or ovate or oblanceolate, 70% of length of lemma, cartilaginous, 2-nerved. Palea apex obtuse. Lodicules 2, lanceolate, membranous. Anthers 3, 0.25–0.3 mm long. Stigmas 2, protandrous, laterally exserted. Grain with adherent pericarp, fusiform, terete, biconvex, estipitate, not grooved, 1.4–1.6 mm long, smooth, apex unappendaged. Embryo 20% of length of grain. Hilum punctiform. Endosperm farinose.

Continental Distribution:
Europe, Africa, Temperate Asia, Australasia, North America, South America, Antarctica.

Australian Distribution:
Western Australia, New South Wales, Victoria, Tasmania.

Western Australia: Menzies, Eyre. New South Wales: Central Coast. Victoria: Wannon, Grampians, Midlands, Victorian Volcanic Plain, Otway Plain, Gippsland Plains, Wilsons Promontory, Snowfields, East Gippsland. Tasmania: North West, North East, West Coast, Central Highlands, Ben Lomond, East Coast, South West, Mt Field, Mt Wellington.

Classification. (GPWG 2001):
Pooideae: Aveneae

Notes
Introduced. Usually a weed of sandy soils. Flowers July–Dec. Fruits Dec.–Jan.

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