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.

Oryzopsis hymenoides

HABIT Perennial; caespitose. Culms erect; 30–70 cm long. Leaves basal and cauline. Ligule an eciliate membrane; 3–7 mm long; entire, or lacerate. Leaf-blades filiform; involute; 10–30 cm long; 1–2 mm wide; coriaceous; stiff. Leaf-blade surface ribbed. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; obovate; effuse; 7–15 cm long. Primary panicle branches spreading; 2 -nate; branching divaricately. Panicle branches capillary.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; curved; 7–30 mm long.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 5–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.8 mm long; pilose.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; gaping. Lower glume ovate; 5–8 mm long; 1 length of upper glume; membranous; without keels; 3 -veined. Lower glume surface glabrous, or puberulous. Lower glume apex attenuate. Upper glume ovate; 5–8 mm long; 1.6–2 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume surface glabrous, or puberulous. Upper glume apex attenuate.

FLORETS Fertile lemma ovate; dorsally compressed; 3–4 mm long; coriaceous; dark brown to black; without keel; 5 -veined. Lemma surface villous. Lemma margins convolute; covering most of palea. Lemma hairs white; 2–4 mm long. Lemma apex obtuse; awned; 1 -awned. Principal lemma awn straight; 3–6 mm long overall; deciduous. Palea coriaceous; 2 -veined; without keels.

FLOWER Styles connate below.

FRUIT Caryopsis apex rostrate.

DISTRIBUTION Asia-temperate: western Asia. North America: western Canada, northwest USA, north-central USA, southwest USA, south-central USA, and Mexico.

NOTES Stipeae. Gould.

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