GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Coix aquatica

HABIT Annual. Culms rambling; 60–150 cm long; spongy. Culm-nodes glabrous. Leaves cauline. Ligule an eciliate membrane; 1 mm long. Leaf-blade base cordate. Leaf-blades linear, or lanceolate; 8–45 cm long; 8–25 mm wide; glandular. Leaf-blade surface pilose; hairy adaxially; with tubercle-based hairs. Leaf-blade margins ciliate. Leaf-blade apex acuminate.

INFLORESCENCE Monoecious; with a male and a female inflorescence subtended by the same spatheole. Synflorescence compound; paniculate; prophyllate below lateral spikelets (female inflorescence). Inflorescence composed of racemes; axillary; deciduous as a whole; subtended by a spatheole; exserted (male), or enclosed (female). Spatheole ovate (and beaked); 10–11 cm long; indurate. Peduncle straight; 3–7 cm long; glabrous; widened at apex; disarticulating; disarticulating below uppermost sheaths.

Racemes 1; single; bearing a triad of spikelets. Rhachis obsolete.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Male spikelets sessile, or pedicelled; 2–3 in a cluster. Pedicels linear; 1 length of fertile spikelet.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 8–9 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes dissimilar; reaching apex of florets; similar to fertile lemma in texture. Lower glume lanceolate, or oblong; 8–9 mm long; 1 length of spikelet; chartaceous; without keels. Lower glume surface flat. Lower glume apex cuspidate. Upper glume oblong; hyaline; 1-keeled. Upper glume primary vein grooved on either side. Upper glume apex cuspidate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate, or oblong; 1 length of spikelet; membranous; 5 -veined; acuminate. Fertile florets female. Fertile lemma lanceolate, or oblong; 7.5–8.5 mm long; membranous; keeled; 5 -veined. Lemma lateral veins obscure. Lemma surface with 2 longitudinal grooves. Lemma apex acuminate. Palea hyaline; 2 -veined; without keels.

FLOWER Lodicules absent (female), or 2 (male); cuneate; fleshy. Anthers 3; 6–6.5 mm long. Stigmas 2; papillose. Styles connate below.

FRUIT Caryopsis with adherent pericarp. Disseminule comprising a inflorescence.

MALE Male inflorescence unlike female; a single raceme. Male spikelets distinct from female; 2 flowered; elliptic; 11–12 mm long (4–6mm wide). Male spikelet glumes 2; winged; muticous. Male spikelet lemma muticous.

DISTRIBUTION Asia-temperate: China. Asia-tropical: India and Indo-China. Australasia: Australia.

NOTES Andropogoneae. Patunkar 1993.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.