Oryza sativa

HABIT Annual. Culms erect, or geniculately ascending; 45–180 cm long; 3–20 -noded. Leaf-sheaths smooth; glabrous on surface. Leaf-sheath auricles erect. Ligule an eciliate membrane; 15–30 mm long; entire, or lacerate; acute. Leaf-blades 12–65 cm long; 4–18 mm wide. Leaf-blade surface scaberulous; rough adaxially; glabrous, or pubescent. Leaf-blade margins scabrous. Leaf-blade apex acute.

INFLORESCENCE Inflorescence a panicle.

Panicle open; lanceolate; equilateral, or nodding; 20–50 cm long. Primary panicle branches appressed, or ascending, or spreading. Panicle branches angular; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear; angular; 2–4 mm long; scaberulous; tip cupuliform; bibracteate.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic, or oblong; laterally compressed; 8–11 mm long; 2.5–3.5 mm wide; persistent on plant. Spikelet callus glabrous; base truncate; attached obliquely.

GLUMES Glumes both absent or obscure.

FLORETS Basal sterile florets similar; barren; without significant palea. Lemma of lower sterile floret lanceolate; 2–3 mm long; 0.25(–0.5) length of spikelet; membranous; without lateral veins; emarginate. Lemma of upper sterile floret lanceolate; 2–3 mm long; 1 length of lower sterile floret; membranous. Fertile lemma elliptic; laterally compressed; 8–11 mm long; coriaceous; keeled; 5 -veined. Lemma midvein ciliate; hairy above. Lemma surface reticulate; glabrous, or hispid. Lemma margins involute. Lemma apex rostrate; muticous, or awned; 1 -awned. Principal lemma awn 0–160 mm long overall; limb scabrous. Palea elliptic; 1 length of lemma; coriaceous; 3 -veined; 1-keeled. Palea keels scabrous. Palea apex acute.

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

FRUIT Caryopsis with adherent pericarp. Disseminule comprising a floret.

DISTRIBUTION Europe: central, southwestern, southeastern, and eastern. Africa: north, Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, south, and western Indian ocean. Asia-temperate: Soviet far east, Soviet Middle Asia, Caucasus, western Asia, Arabia, China, Mongolia, and eastern Asia. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, northwestern, and north-central. North America: southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Oryzeae. FZ.

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