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 rufipogon

HABIT Perennial. Rhizomes elongated; spongy. Culms geniculately ascending, or decumbent; 30–100 cm long; spongy. Leaf-sheaths smooth; glabrous on surface. Leaf-sheath auricles erect. Ligule an eciliate membrane; 12–17 mm long; lacerate. Leaf-blades 20–40 cm long; 5–10 mm wide. Leaf-blade surface scabrous. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; nodding; 10–20 cm long. Primary panicle branches appressed; simple. Panicle branches scabrous.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels linear; angular; tip cupuliform.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; 8–9 mm long; 2–2.5 mm wide; falling entire. Rhachilla internodes elongated below proximal fertile floret. Rhachilla elongation stout; 0.5 mm long.

GLUMES Glumes both absent or obscure.

FLORETS Basal sterile florets similar; barren; without significant palea. Lemma of lower sterile floret linear, or oblong; 2.4 mm long; 0.25 length of spikelet; 1 -veined; without lateral veins. Lemma of upper sterile floret linear, or oblong; 2.4 mm long; 1 length of lower sterile floret. Fertile lemma oblong; laterally compressed; 7 mm long; coriaceous; keeled; 5 -veined. Lemma midvein spinulose. Lemma surface scaberulous and reticulate. Lemma margins interlocking with palea margins. Lemma apex awned; 1 -awned. Principal lemma awn 60–70 mm long overall; limb scabrous. Palea elliptic; 7 mm long; coriaceous; 3 -veined; 1-keeled. Palea surface scabrous. Palea apex acute; muticous, or awned; awns 0–6 mm long.

FLOWER Lodicules 2; membranous. Anthers 6; 5 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Disseminule comprising a floret.

DISTRIBUTION Asia-temperate: China and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. South America: Mesoamericana, Caribbean, northern South America, western South America, and southern South America.

NOTES Oryzeae. Fl Ceyl.

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