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.

Oryza officinalis

HABIT Perennial; caespitose. Culms geniculately ascending, or decumbent; robust; 120–150 cm long. Leaf-sheaths smooth; glabrous on surface. Leaf-sheath auricles absent. Ligule an eciliate membrane; 3–5 mm long; erose; obtuse. Leaf-blades 25–50 cm long; 10–20 mm wide. Leaf-blade surface scaberulous; rough on both sides. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle; comprising 6–20 fertile spikelets.

Panicle open; ovate; 20–40 cm long. Primary panicle branches spreading, or drooping; 2–4 -nate; whorled at lower nodes; simple; 10–15 cm long. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear; angular; 0.5 length of fertile spikelet.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic, or ovate; laterally compressed; 4–5 mm long; 2–2.4 mm wide; falling entire.

GLUMES Glumes both absent or obscure.

FLORETS Basal sterile florets similar; barren; without significant palea. Lemma of lower sterile floret lanceolate; 1.5 mm long; 0.3–0.4 length of spikelet; 1 -veined; without lateral veins; acuminate. Lemma of upper sterile floret lanceolate; 1.5 mm long; 1 length of lower sterile floret. Fertile lemma oblong, or orbicular; laterally compressed; 4–5 mm long; coriaceous; dark brown, or black; keeled; 5 -veined. Lemma midvein spinulose. Lemma surface scabrous and reticulate. Lemma margins interlocking with palea margins. Lemma apex awned; 1 -awned. Principal lemma awn 3–18 mm long overall. Palea elliptic; coriaceous; 3 -veined; 1-keeled. Palea keels spinulose. Palea surface scaberulous. Palea apex acute; awned; awns 1 mm long.

FLOWER Lodicules 2; membranous. Anthers 6; 2.5 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Disseminule comprising a spikelet.

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

NOTES Oryzeae. Fl Ceyl.

ADDITIONAL CHARACTERS Panicle branches naked in lower half.

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