Common name
Bulbous Oatgrass
False Oatgrass
Oat Grass
Bulbous False Oat
False Oat
Onion Twitch

Derivation
Arrhenatherum P.Beauv., Ess. Agrostogr. 55, 152, 153, t. 11, fig. 5 (1812); from the Greek arrhen, male, and ather, awn, alluding to the awn of the male floret.

elatius- Latin for taller. Culms taller than those of related species.

Published in
Fl. Friburg 1: 113 (1825).

Habit
Perennial, tufted. Culms erect, 50–180 cm tall, 3–5-noded, not swollen at the base or swollen at the base, forming moniliform corms. Mid-culm nodes glabrous or pubescent. Leaves cauline. Leaf-sheaths smooth or scaberulous, glabrous on surface or pilose. Ligule an eciliate membrane, 0.5–2(–3) mm long. Leaf-blades 10–23(–40) cm long, 4–10 mm wide. Leaf-blade surface scaberulous, pilose.

Inflorescence
Inflorescence compound, a panicle. Panicle open or contracted, lanceolate or oblong, equilateral or nodding, 9–30 cm long.

Spikelets
Spikelets solitary. Pedicels filiform or linear, 1–10 mm long. Fertile spikelets 1-flowered or 2-flowered or many flowered, comprising 1(–3) fertile floret(s), with a barren rhachilla extension, oblong, laterally compressed, 7–11 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Rhachilla internodes elongated below proximal fertile floret. Floret callus pilose.

Glumes
Glumes persistent, dissimilar, thinner than fertile lemma, shiny, gaping. Lower glume lanceolate, (3–)4–6(–7) mm long, 60% length of upper glume, membranous, 1-keeled, 1-nerved, midnerve scaberulous. Lower glume lateral nerves absent. Lower glume apex acute. Upper glume ovate, 7–11 mm long, 90–100% of length of adjacent fertile lemma, membranous, 1-keeled, 3(–5)-nerved, midnerve scaberulous. Upper glume apex acute.

Florets
Basal sterile floret 1, with palea, attached to and deciduous with the fertile. Lemma of lower sterile floret ovate, chartaceous, much thinner above, 7-nerved, glabrous or pilose, dentate, 2-fid, awned. Awn of lower sterile floret dorsal (on lower third of lemma), geniculate, 10–20 mm long. Fertile lemma elliptic or ovate or obovate, 7–10 mm long, chartaceous, much thinner above, keeled above, 7-nerved. Lemma surface glabrous or pilose (below when pilose). Lemma apex dentate, 2-fid, muticous or 1-awned. Median (principal) awn subapical, straight or geniculate, flexible, 0.9–12 mm long overall, with a twisted column. Palea keels ciliolate. Anthers 3, 3.7–5.2(–5.5) mm long. Ovary pubescent all over.

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

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

Western Australia: Drummond, Menzies, Warren. South Australia: Northern Lofty, Southern Lofty, South-eastern. Queensland: Moreton, Wide Bay. New South Wales: North Coast, Central Coast, South Coast, Northern Tablelands, Central Tablelands, Southern Tablelands, North-Western Slopes, Central-Western Slopes, South-Western Slopes. Victoria: Riverina, Midlands, Victorian Volcanic Plain, Otway Range, Eastern Highlands, Gippsland Plains, Gippsland Highlands, East Gippsland. Tasmania: Furneaux Group, North West, North East, West Coast, Midlands, East Coast.

Classification. (GPWG 2001):
Pooideae: Aveneae

Notes
Native of Asia, now widespread in Europe, Africa and North America. A weed of dry grasslands. Flowers Nov.–Jan. There are two varieties:

Arrhenatherum elatius (L.) P.Beauv. ex J.Presl & C.Presl var. elatius
A weed of dry grasslands. Flowers Nov.–Jan. Fruits Nov.

Arrhenatherum elatius (L.) P.Beauv. ex J.Presl & C.Presl var. bulbosum (Willd.) Spenner
A weed of roadsides and perennial crops, particularly in areas of high rainfall. Flowers Nov.–Feb. Fruits Nov. Ornamental form with striped green and yellow leaves also seen from Canberra.

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