GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Deyeuxia tacomensis

HABIT Perennial; caespitose; clumped moderately, or densely. Rhizomes absent, or short. Culms (20–)30–55(–95) cm long; (1–)2(–5) -noded. Culm-internodes smooth. Lateral branches lacking. Leaf-sheaths smooth. Ligule an eciliate membrane; (3–)3.5–5.5(–6) mm long; entire, or lacerate; truncate, or obtuse. Leaf-blades (6–)7–14(–30) cm long; 1.5–4 mm wide. Leaf-blade surface smooth, or scaberulous; rough abaxially, or on both sides; pubescent; sparsely hairy; hairy adaxially.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth, or scaberulous above.

Panicle open, or contracted; linear, or lanceolate; equilateral, or nodding; (5–)7–10(–18) cm long; (0.5–)1–2(–3) cm wide. Primary panicle branches (2–)2.3–4(–6) cm long; naked below, or bearing spikelets almost to the base. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; laterally compressed; (4–)6–6.5(–7) mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus bearded. Floret callus hairs 1.2–2.5 mm long; 0.3–0.6 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 surface smooth, or asperulous. Lower glume apex acute. Upper glume lanceolate; (4–)6–6.5(–7) mm long; 1.3–1.5 length of adjacent fertile lemma; membranous; 1-keeled; 1–3 -veined. Upper glume lateral veins absent, or prominent. Upper glume surface smooth, or asperulous; rough above. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; (3.5–)4–5(–5.5) mm long; membranous; without keel; 5 -veined. Lemma apex awned; 1 -awned. Principal lemma awn dorsal; arising 0.1–0.33 way up back of lemma; geniculate; (5.5–)7–8.5(–10) mm long overall; clearly exserted from spikelet; with twisted column. Rhachilla extension 1.5–2(–2.5) mm long; pilose; with 1.5–3 mm long hairs.

FLOWER Anthers 3; (1–)2–3(–3.5) mm long.

DISTRIBUTION North America: northwest USA.

NOTES Aveneae. Fl N Amer 2007.

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