Deyeuxia howellii

HABIT Perennial; caespitose. Culms 30–50 cm long. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 3–6 mm long; erose; acute. Leaf-blades conduplicate, or involute; 1–2.5 mm wide. Leaf-blade surface scaberulous; rough adaxially. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 5–15 cm long. Primary panicle branches spreading; whorled at lower nodes; 3–5 cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; laterally compressed; 6–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus bearded. Floret callus hairs 1.5–3 mm long; 0.25–0.5 length of lemma.

GLUMES Glumes persistent; similar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 6–7 mm long; 1.2 length of adjacent fertile lemma; membranous; 1-keeled; 1–3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate; 5 mm long; membranous; without keel; 5 -veined. Lemma lateral veins excurrent. Lemma apex dentate; 4 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.4 way up back of lemma; geniculate; 10–15 mm long overall; with twisted column. Palea 0.75 length of lemma. Rhachilla extension 0.5 length of fertile floret; pilose.

FLOWER Lodicules 2; 1 mm long. Anthers 3; 3 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform. Disseminule comprising a floret.

DISTRIBUTION North America: northwest USA.

NOTES Aveneae. Fl Pac NW 1994.

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