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 ridleyi

HABIT Perennial. Culms geniculately ascending, or decumbent; 100–150 cm long. Leaf-sheaths smooth; glabrous on surface. Ligule an eciliate membrane; 3–5 mm long. Leaf-blades 15–30 cm long; 15–25 mm wide. Leaf-blade surface smooth. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; 25–35 cm long; 10–15 cm wide. Primary panicle branches ascending; simple; 6–12 cm long. Panicle branches scaberulous.

Spikelets appressed. 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; 2.5 mm wide; falling entire. Rhachilla internodes elongated below proximal fertile floret. Rhachilla elongation 0.6 mm long.

GLUMES Glumes both absent or obscure.

FLORETS Basal sterile florets similar; barren; without significant palea. Lemma of lower sterile floret subulate; 6–7.5 mm long; 0.8 length of spikelet; scaberulous. Lemma of upper sterile floret subulate; 6–7.5 mm long; 1 length of lower sterile floret. Fertile lemma elliptic; laterally compressed; 7–8 mm long; coriaceous; keeled; 5 -veined. Lemma midvein spinulose. Lemma surface scaberulous; rough on veins. Lemma margins interlocking with palea margins. Lemma apex awned; 1 -awned. Principal lemma awn 4–8 mm long overall. Palea elliptic; 9 mm long; coriaceous; 3 -veined; 1-keeled. Palea keels spinulose. Palea apex acuminate; with excurrent keel veins.

FLOWER Lodicules 2; membranous. Anthers 6. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Disseminule comprising a floret.

DISTRIBUTION Asia-tropical: Indo-China, Malesia, and Papuasia.

NOTES Oryzeae. Fl Ceyl.

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