Deyeuxia coahuilensis

HABIT Perennial; caespitose. Butt sheaths persistent and investing base of culm; with compacted dead sheaths, or fibrous dead sheaths. Basal innovations extravaginal and intravaginal. Culms erect; (22–)40–100 cm long. Culm-internodes distally glabrous. Lateral branches lacking. Leaf-sheaths 6–8 cm long; mostly shorter than adjacent culm internode; glabrous on surface. Ligule an eciliate membrane; 5–8 mm long; entire, or lacerate; truncate. Leaf-blades 8–20 cm long; 2–4 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 9–20 cm long; 0.5–1.2 cm wide. Primary panicle branches appressed, or ascending; 1–2 -nate; 2–10 cm long; bearing spikelets almost to the base. Panicle axis scaberulous.

Spikelets appressed; solitary. Fertile spikelets pedicelled. Pedicels 0.6–4 mm long; scaberulous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; laterally compressed; 5.8–7.2 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose. Floret callus hairs 0.8–1.8 mm long; 0.33–0.66 length of lemma.

GLUMES Glumes persistent; similar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 5.8–7.2 mm long; 1 length of upper glume; membranous; much thinner on margins; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 5–5.7 mm long; 1.1–1.2 length of adjacent fertile lemma; membranous; with hyaline margins; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume surface asperulous. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 5–5.7 mm long; membranous; without keel; 5 -veined. Lemma lateral veins prominent. Lemma surface scaberulous. Lemma apex entire, or dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0–0.15 way up back of lemma; geniculate; 8–10 mm long overall; with twisted column. Palea 1 length of lemma; 2 -veined. Palea keels scaberulous. Rhachilla extension 2.4–3 mm long; pilose; with 0.5–1 mm long hairs.

FLOWER Lodicules 2; lanceolate; 1 mm long; emarginate. Anthers 3; 1–1.2 mm long; purple. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; fusiform; 2–2.5 mm long; green. Hilum punctiform. Disseminule comprising a floret.

DISTRIBUTION North America: Mexico.

NOTES Aveneae. Peterson et al 2006.

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