Aristida contorta

Aristida
contorta
F.Muell. Trans.
& Proc. Vict. Inst. Advancem. Sci.
1:44 (1855). Classification. (GPWG 2001) : Subfamily Aristidoideae. Aristideae.

Type of Basionym or
Protologue Information
: HT: Mueller s.n., Australia: Victoria: on
barren places on the Murray River (MEL (photo, BRI); IT: BRI, E, K).

Recent synonyms:
Aristida arenaria Gaudich.

Key references
(books and floras):
[1878] G.Bentham, Flora Australiensis 7 (561 as Aristida
arenaria
), [1952] C.A.Gardner, Flora of Western Australia 1 Gramineae
(165 as A. arenaria), [1981] M.Lazarides in J.Jessop (ed)., Flora of
Central Australia
(452), [2002] D.Sharp & B.K.Simon, AusGrass,
Grasses of Australia
, [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses
of South Australia
(322), [2008] S.W.L.Jacobs, R.D.B.Walley &
D.J.B.Wheeler, Grasses of New South Wales (127).

Illustrations:
[1952] C.A.Gardner, Flora of Western Australia 1 Gramineae (161,
Pl.48 as A. arenaria), [1983] J.C.Tothill & J.B.Hacker, Grasses
of Southern Queensland
(104(9)), [2005] K.Mallet (ed.), Flora of
Australia
44B: Poaceae 3 (Fig. 14A), [2006] J.Jessop,
G.R.M.Dashorst, F.M.James, Grasses of South Australia  (322, Fig. 254), [2008] S.W.L.Jacobs,
R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th edn
(128).

Habit. Annual
or perennial. Culms erect or geniculately ascending, 12–44 cm tall, 2–4 -noded.
Mid-culm internodes glabrous. Lateral branches branched. Leaf-sheaths smooth or
scaberulous, glabrous on surface or hairy. Ligule a fringe of hairs, 0.3–0.5 mm
long. Leaf-blades flexuous, filiform, conduplicate or involute or convolute,
3–10 cm long, 1 mm wide. Leaf-blade surface smooth or scaberulous, glabrous or
indumented.

Inflorescence.
Inflorescence compound, a panicle. Panicle elliptic, 9–26 cm long, 4–9 cm wide.

Spikelets.
Spikelets pedicelled. Fertile spikelets 1-flowered, comprising 1 fertile
floret(s), without rachilla extension, lanceolate, laterally compressed, 12–30
mm long.

Glumes.
Glumes similar, thinner than fertile lemma. Lower glume lanceolate, membranous,
keeled, 1-keeled, 1 -nerved. Lower glume surface glabrous. Upper glume
lanceolate, 12–30 mm long, membranous, keeled, 1-keeled, 1 -nerved. Upper glume
surface asperulous or scabrous, glabrous. Upper glume apex muticous or mucronate.

Florets.
Fertile lemma 4.9–7 mm long, without keel, 3 -nerved. Lemma apex awned, 3
-awned. Median (principal) awn 25–121 mm long overall, with a twisted column.
Column 7–26 mm long. Lateral lemma awns present. Palea without keels. Anthers
3. Grain 3–4.5 mm long.

Continental
Distribution
: Australasia.

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

Western Australia:
Fitzgerald, Hall. Giles, Helms, Fortescue, Ashburton, Carnarvon, Austin. Irwin,
Eyre, Roe, Avon. Northern Territory: Victoria River, Barkly Tableland,
Central Australia North, Central Australia South. South Australia:
North-western, Lake Eyre, Nullabor, Gairdner-Torrens Basin, Flinders Ranges,
Eastern, Eyre Peninsula, Northern Lofty, Murray, Southern Lofty. Queensland:
Burke, Burnett, Darling Downs, Gregory North, Maranoa, Gregory South, Port
Curtis, South Kennedy, Warrego, North Kennedy, Mitchell. New South Wales:
Central-Western Slopes, North-Western Plains, South-Western Plains, North Far
Western Plains, South Far Western Plains. Victoria: Murray Mallee.

Notes.
A. contorta is extremely variable in habit depending on the availability
of moisture. It is close to A. holathera, with which it probably
hybridises, and differs by the culms being ± wavy and the lemma being 7 mm or
less long and becoming brownish when mature, as opposed to purplish in A.
holathera
. Ecologically A. contorta is adapted to the driest regions
of Australia.

Arid and semi-arid
regions of all mainland states. Eucalyptus and mulga (Acacia aneura)
woodlands on desert red earths, sandy and alluvial soils. Flowering and
fruiting all year.


AVH 2011                

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith