Common name
Threeawn Speargrass

Derivation
Aristida L., Sp. Pl. 1: 82 (1753); from the Latin arista (an awn).

vagans- from the Latin vago (wander), derivation from the branching culms.

Published in
Icon. Desc. Pl. 5: 45 (1799).

Habit
Perennial, tufted. Culms 38–85 cm tall, 2–3-noded. Mid-culm internodes smooth, glabrous. Lateral branches simple or sparsely branched or branched. Leaf-sheaths glabrous on surface. Ligule a fringe of hairs, 0.5 mm long. Collar glabrous. Leaf-blades straight, flat or conduplicate or involute or convolute, 5–12 cm long, 1–1.5 mm wide. Leaf-blade surface scabrous, glabrous or pilose.

Inflorescence
Inflorescence compound, a panicle. Panicle open, ovate, 6–11.5 cm long, 3–4 cm wide. Primary panicle branches 2–5 cm long. Panicle branches with prominent pulvini.

Spikelets
Spikelets solitary. Fertile spikelets 1-flowered, comprising 1 fertile floret, without rhachilla extension, lanceolate, terete, 8.5–12 mm long, breaking up at maturity. Spikelets disarticulating below each fertile floret. Floret callus elongated, pubescent, acute.

Glumes
Glumes persistent, similar, thinner than fertile lemma. Lower glume lanceolate, 3.5–7 mm long, equalling upper glume, membranous, 1-keeled, 1-nerved. Lower glume lateral nerves absent. Lower glume apex cuspidate, mucronate. Upper glume lanceolate, 3.5–7 mm long, 40–60% of length of adjacent fertile lemma, membranous, 1-keeled, 1-nerved. Upper glume lateral nerves absent. Upper glume apex entire or erose, emarginate or obtuse.

Florets
Fertile lemma lanceolate, subterete, 8.5–12 mm long, coriaceous, 3-nerved. Lemma surface smooth. Lemma margins convolute, covering most of palea. Lemma apex acute, 3-awned. Median (principal) awn 6–9.5 mm long, without a column, persistent. Lateral lemma awns present, 4–8 mm long, shorter than principal, 45–84% of length of principal. Palea 20% of length of lemma, without keels. Anthers 3. Grain with adherent pericarp, terete, not grooved, 6–9 mm long. Embryo 25–50% of length of grain. Hilum linear, 30–40% of length of caryopsis.

Continental Distribution:
Australasia.

Australian Distribution:
Queensland, New South Wales.

Queensland: Port Curtis, Burnett, Darling Downs, Moreton, Wide Bay. New South Wales: North Coast, Central Coast, South Coast, Northern Tablelands, Central Tablelands, North-Western Slopes, Central-Western Slopes, North-Western Plains.

Classification. (GPWG 2001):
Aristidoideae

Notes
Native. South-east coastal Australia from south-eastern Queensland to the Victorian border; two records from outside this range. Eucalyptus communities on rocky and sandy soils. Flowering and fruiting all year. Aristida vagans is similar to Aristida caput-medusae in having small spikelets in which the lemma extends beyond the glumes, but it differs from this species by the inflorescence being larger and irregular in outline.

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