Oryzopsis arnowiae

HABIT Perennial; caespitose; clumped densely. Butt sheaths persistent and investing base of culm. Culms erect; 15–75 cm long. Leaf-sheaths outer margin hairy. Leaf-sheath oral hairs lacking, or ciliate. Ligule an eciliate membrane; 1–4 mm long. Leaf-blades involute; 2 mm wide. Leaf-blade surface smooth, or scaberulous. Leaf-blade apex attenuate; simple, or filiform.

INFLORESCENCE Inflorescence a panicle; exserted, or embraced at base by subtending leaf.

Panicle contracted; linear; 5–20 cm long; 0.5–2.8 cm wide. Primary panicle branches appressed, or ascending; 0.5–2.5(–5) cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 5.1–6.1 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.2–0.4 mm long.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume ovate; 5.1–6.1 mm long; 1.2 length of upper glume; membranous; without keels; 3 -veined. Lower glume lateral veins prominent. Lower glume surface puberulous. Lower glume apex acuminate. Upper glume ovate; 4.3–5.2 mm long; 1.4–1.5 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume lateral veins prominent. Upper glume surface puberulous. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; dorsally compressed; 2.9–3.7 mm long; coriaceous; without keel; 5 -veined. Lemma surface hirsute; hairy on back, or on veins. Lemma margins convolute; covering most of palea. Lemma hairs white; 2–3 mm long. Lemma apex awned; 1 -awned. Principal lemma awn straight; 3–4.4 mm long overall; deciduous. Palea coriaceous; 2 -veined; without keels.

FLOWER Anthers 3; 1 mm long.

DISTRIBUTION North America: southwest USA.

NOTES Stipeae. Utah Gr 2007.

ADDITIONAL CHARACTERS Lemma less than 3 times as long as wide.

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