Leersia hexandra Sw.
|
Common name
Swamp Rice Grass
Derivation
Leersia Sw., Prodr. 21 (1788); Named for Johan Daniel Leers, a
German apothecary and botanist of the 18th century.
hexandra- from the Greek hexa (six) and aner (man). The florets possess six anthers.
Published in
Prodr. 21 (1788).
Habit
Annual or perennial. Rhizomes elongated. Basal leaf sheaths glabrous. Culms
erect or geniculately ascending or decumbent or clambering or aquatic, 30150
cm tall. Mid-culm nodes pubescent. Lateral branches simple. Ligule an eciliate
membrane, 12 mm long, scarious, truncate. Leaf-blades 620 cm long,
216 mm wide. Leaf-blade surface scaberulous. Leaf-blade margins scabrous.
Inflorescence
Inflorescence compound, a panicle. Panicle open, elliptic or oblong, 513.5
cm long, 14 cm wide. Primary panicle branches bearing spikelets almost
to the base.
Spikelets
Spikelets solitary. Fertile spikelets 1-flowered, comprising 1 fertile floret,
without rhachilla extension, oblong, strongly laterally compressed, (3.2)3.44.8(5.2)
mm long, (1)1.21.4(1.7) mm wide, falling entire.
Glumes
Both glumes absent or obscure.
Florets
Fertile lemma oblong in profile, (3.2)3.44.8(5.2) mm long,
chartaceous, pallid or purple, 5-nerved. Lemma midnerve pectinately ciliate
or hispid. Lemma surface scabrous. Lemma margins involute. Lemma apex acute
or acuminate or caudate, muticous. Palea present, elliptic, 100% of length
of lemma, chartaceous, 3-nerved, 1-keeled. Palea keels pectinate. Palea apex
entire. Lodicules 2. Anthers 6. Stigmas 2.
Continental Distribution:
Africa, Temperate Asia, Tropical Asia, Australasia, North America, South America.
Australian Distribution:
Northern Territory, Queensland, New South Wales.
Northern Territory: Darwin & Gulf. Queensland: Cook, North Kennedy, South Kennedy, Port Curtis, Leichhardt, Burnett, Wide Bay, Darling Downs, Moreton. New South Wales: North Coast, Central Coast.
Classification. (GPWG
2001):
Ehrhartoideae: Oryzeae
Notes
Native. Widely distributed throughout the tropics. Usually in swamps and creeks,
waterholes, lakes; substrate sand, peat, clay. Flowers Mar.Sept.
Inflorescence (photo)
© D. Sharp
Inflorescence and spikelet (line drawing)
© Australian Biological Resources Study
drawing by Nicola Oram