Common name
Bull Mitchell Grass

Derivation
Astrebla F.Muell. ex Benth., Fl. Austral. 7: 602 (1878); from the Greek a (not) and streblos (twisted), in reference to the straight awns.

squarrosa- Latin for spreading at right angles from a common axis.

Published in
Bull. Misc. Inform. 259 (1928).

Habit
Perennial, tufted. Rhizomes short. Culms erect, 20–150 cm tall. Lateral branches branched, arising from upper culm. Ligule a fringe of hairs. Leaf-blades flat or conduplicate, 7–40(–50) cm long, 3–6 mm wide. Leaf-blade surface scabrous. Leaf-blade margins scaberulous. Leaf-blade apex filiform.

Inflorescence
Inflorescence solid, a raceme, embraced at base by subtending leaf. Racemes 1, unilateral, (4–)7–18 cm long, 15–30 mm wide. Rhachis flattened, scabrous on surface. Spikelet packing broadside to rhachis, regular, 2-rowed.

Spikelets
Spikelets solitary. Pedicels oblong, 1.5–2.5 mm long, scaberulous. Fertile spikelets 2-flowered or many-flowered, comprising 2–4 fertile florets, with diminished florets at the apex, ovate, laterally compressed, 8–25 mm long, breaking up at maturity. Spikelets disarticulating above glumes but not between florets.

Glumes
Glumes persistent, dissimilar, thinner than fertile lemma. Lower glume lanceolate, 5–10 mm long, 80–90% length of upper glume, chartaceous, 1-keeled, 1–3-nerved. Lower glume apex acuminate, mucronate. Upper glume elliptic, 6–11 mm long, equalling adjacent fertile lemma, chartaceous, 9–11-nerved. Upper glume apex acuminate, mucronate.

Florets
Fertile lemma elliptic or oblong, 4.5–7 mm long, 4.5–5.5 mm wide, coriaceous, much thinner above, 3-nerved (in the body). Lemma lateral nerves augmented by subsidiaries in lobes. Lemma surface villous. Lemma apex lobed, 3-fid, with outer lobes longer, incised 40–50% of lemma length, 3-awned. Median (principal) awn hooked, 5 mm long overall. Lateral lemma awns present, 3–4 mm long, shorter than principal. Palea 60–70% of length of lemma. Palea keels ciliate. Palea apex lobed, 2-fid. Apical sterile florets resembling fertile though underdeveloped. Lodicules 2, cuneate, fleshy, truncate. Anthers 3, 1–3 mm long. Grain with adherent pericarp, ellipsoid, dorsally compressed, 2.5–3 mm long. Hilum punctiform.

Continental Distribution:
Australasia.

Australian Distribution:
Western Australia, Northern Territory, South Australia, Queensland, New South Wales.

Western Australia: Gardner, Fitzgerald, Hall. Northern Territory: Darwin & Gulf, Victoria River, Barkly Tableland. South Australia: Lake Eyre. Queensland: Cook, Burke, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Gregory North, Gregory South, Mitchell, Warrego, Maranoa. New South Wales: North-Western Plains.

Classification. (GPWG 2001):
Chloridoideae: Cynodonteae

Notes
Native. Distributed from the Kimberley region of W.A. across the northern part of the N.T. and through most of Qld, just reaching northern N.S.W. and the NE corner of S.A. It usually occurs as a minor element in communities dominated by A. lappacea or A. pectinata and reaches its highest frequency on lower-lying ground which receives run-off from adjacent areas. On the Barkly Tableland A. squarrosa extends farther N to higher rainfall areas than either A. pectinata or A. elymoides and in these areas it sometimes occurs as relatively pure stands. It has been reported from heavy, cracking clays of all colours on plains and river flats, sometimes with Lysiphyllum or Excoecaria, or in Dicanthium-Eulalia grassland and cleared Brigalow areas; flowers after rain.

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