Tetrarrhena acuminata

Tetrarrhena acuminata R. Br. Prodr. 210 (1810).

Classification. (GPWG 2001) : Subfamily Ehrhartoideae. Tribe Ehrharteae.

Type of Basionym or Protologue Information: Tasmania:  Brown 6167 (K iso).

Key references (books and floras): [1810]. R.Brown, Prodromus (210), [1878] G.Bentham, Flora Australiensis 7 (554), [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of Australia, [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses of South Australia (60), [2009] A.Wilson (ed.). Flora of Australia, Vol 44A. Poaceae 2 (377).

Illustrations: [2006] J.Jessop, G.R.M.Dashorst, F.M.James, Grasses of South Australia  (60, fig. 24).

Habit. Perennial. Rhizomes present. Stolons present. Culms erect or geniculately ascending, stature slender to delicate, 6–60 cm tall. Mid-culm internodes glabrous. Leaf-sheath auricles absent. Ligule an eciliate membrane, 0.3–0.5 mm long, membranous, abaxially glabrous, erose. Leaf-blades flat, 1–12 cm long, 1–4 mm wide. Leaf-blade surface glabrous.

Inflorescence. Inflorescence solid, a raceme. Racemes 1, 0.5–5 cm long, bearing 2–10 fertile spikelets on each.

Spikelets. Spikelets sessile or pedicelled. Fertile spikelets 1-flowered, comprising 2 basal sterile florets, comprising 1 fertile floret(s), without rachilla extension, oblong, laterally compressed, 5–10 mm long.

Glumes. Glumes similar, thinner than fertile lemma. Lower glume oblate, hyaline, without keels or keeled, 1 -nerved. Upper glume ovate, 1–1.7 mm long, hyaline, without keels, 1 -nerved. Florets. Basal sterile florets 2 or more, barren, without significant palea. Lemma of lower sterile floret 75 % of length of spikelet, coriaceous, 1-keeled, 5 -nerved, mucronate. Lemma of upper sterile floret 6–10 mm long, mucronate.

Fertile lemma 4.8–7.3 mm long, keeled, 7(–9) -nerved. Lemma surface glabrous. Palea 1 -nerved. Lodicules present. Anthers 4.

Continental Distribution: Australasia.

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

South Australia: South-eastern. Victoria: East Gippsland, Gippsland Plain, Grampians, Otway Range, Wilsons Promontory, Wannon. Tasmania: Furneaux Group, West Coast, Central Highlands, Ben Lomond, South West.

Notes. Often in damp sites. Flowers Dec.-Jan.


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