Eriachne avenacea R. Br. Prodr.
184 (1810).
Classification. (GPWG 2001) : Subfamily Micrairoideae. Eriachneae.
Type of Basionym or
Protologue Information: HT: R. Brown 6263, 14 Feb 1803, Australia:
Northern Territory, Darwin and Gulf District, Cavern Island (BM; IT: B, BR, C,
CANB, E, F, G, K, US-734047).
Recent synonyms:
E. setacea.
Key references
(books and floras): [1810]. R.Brown, Prodromus (184), [1878]
G.Bentham, Flora Australiensis 7 (629 asEriachne setacea, Eriachne
avenacea), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of
Australia.
Illustrations:
[2005] K.Mallet (ed.), Flora of Australia 44B: Poaceae 3 (Fig.
26R-T).
Habit. Annual
or perennial. Culms erect or geniculately ascending, stature slender to
delicate, 17–68 cm tall, 3–6 -noded. Mid-culm internodes glabrous or hispid.
Mid-culm nodes glabrous or pubescent. Lateral branches simple or sparsely
branched or branched or fastigiate. Ligule a fringe of hairs, 0.3–0.5 mm long.
Leaf-blades filiform, involute, 10–20 cm long, 1 mm wide. Leaf-blade surface
glabrous or indumented.
Inflorescence.
Inflorescence compound, a panicle or a panicle. Panicle linear or oblong or
ovate, 2.5–7 cm long, 0.5–5 cm wide.
Spikelets.
Spikelets pedicelled. Fertile spikelets 2-flowered, both fertile, comprising 2
fertile floret(s), without rachilla extension, ovate, laterally compressed,
4.8–9 mm long.
Glumes.
Glumes similar, thinner than fertile lemma. Lower glume elliptic, membranous,
without keels, 9–13 -nerved. Lower glume surface glabrous or indumented. Lower
glume apex muticous or mucronate. Upper glume elliptic, 4.5–8 mm long,
membranous, without keels, 9–13 -nerved. Upper glume surface smooth, glabrous or
indumented. Upper glume apex muticous or mucronate.
Florets.
Fertile lemma 4.5–9 mm long, without keel, 5–7 -nerved. Lemma surface
indumented. Lemma apex awned, 1 -awned. Median (principal) awn 0.5–6 mm long
overall. Palea apex entire or dentate, muticous. Grain 2.5–4.3 mm long.
Continental
Distribution: Australasia.
Australian
Distribution: Western Australia, Northern Territory.
Western Australia:
Gardner, Fitzgerald. Northern Territory: Darwin & Gulf, Victoria
River.
Notes.
Variable in duration, panicle form, the indumentum of the glumes, leaves and
culm nodes, spikelet dimensions, and in the length of the lemma awn. However,
it is readily distinguished from E. setacea by its compact habit,
extremely thin culms and blades, strongly many-nerved glumes, and by the long,
submarginal indumentum on its lemmas. It has close similarities with E.
melicacea and E. bleeseri, differing from the former by its awned
lemmas and glabrous palea margins, and from the latter by its many-nerved
glumes, florets longer than glumes, and its ciliate lemmas with longer awns.
Endemic.
N.T. and W.A., N of 18ºS. Recorded habitats include deep or skeletal, sandy or
podsolic, pebbly or gravelly or stony soils over sandstone or laterite, on
sandplains, hillslopes or ridges, seasonally wet floodplains, depression flats,
creek beds and valley floors, and sometimes disturbed ground. Flowers and
fruits Jan.-Oct. (all seasons).
