Hygrochloa aquatica M. Lazarides. Brunonia 2: 87 (1979).
Classification. (GPWG 2001) : Subfamily Panicoideae. Paniceae.
Type of Basionym or
Protologue Information: Australia: Northern Territory: Darwin & Gulf
Distr.: near Howard Springs, 12.25S 131.05E, 29 Jun 1977, Craven 4462
(HT: CANB; IT: BRI, K, NT).
Key references
(books and floras): [2002] D.Sharp & B.K.Simon, AusGrass, Grasses of
Australia.
Habit. Annual
or perennial. Culms decumbent or prostrate (floating), 15–200 cm tall (long),
spongy. Lateral branches sparsely branched. Ligule a fringe of hairs, 0.3–0.8
mm long. Leaf-blades floating, linear, flat, 2–16 cm long, 2.5–6 mm wide.
Leaf-blade surface papillose.
Inflorescence.
Inflorescence compound, a panicle of racemes. Racemes 5–10, appressed, 1 cm
long, bearing 1–4 fertile spikelets on each. Central inflorescence axis 4–10 cm
long.
Spikelets.
Spikelets sessile. Male spikelets sessile. Fertile spikelets 2-flowered, the
lower floret barren (rarely male), the upper fertile, comprising 1 basal
sterile florets, comprising 1 fertile floret(s), without rachilla extension,
elliptic, dorsally compressed, 2–2.8 mm long.
Glumes. Glumes
dissimilar, thinner than fertile lemma. Lower glume orbicular, membranous,
without keels, 0 -nerved. Upper glume ovate, 1.2–2.3 mm long, membranous,
without keels, 5(–7) -nerved. Upper glume apex entire or lobed. Florets.
Basal sterile florets 1, barren, without significant palea. Lemma of lower
sterile floret 100 % of length of spikelet, membranous, 5(–7) -nerved. Fertile
florets female.
Fertile lemma 1.9–2.7
mm long, without keel, 5 -nerved. Palea 2 -nerved. Anthers 3.
Continental
Distribution: Australasia.
Australian
Distribution: Western Australia, Northern Territory.
Northern Territory:
Darwin & Gulf.
Notes.
Hygrochloa aquatica has specialized culm and leaf characteristics
adapted to aquatic conditions.
In tropical and
subtropical sub-humid woodlands and coastal grasslands. Flowers Jan.-July.
