Festuca occidentalis

HABIT Perennial; caespitose. Culms 60–110 cm long. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 0.5 mm long. Collar glabrous. Leaf-blades filiform; conduplicate; 0.5–1 mm wide. Leaf-blade surface scaberulous; rough adaxially; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; loose; 10–20 cm long. Primary panicle branches drooping; 1–2 -nate.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4–6 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 6–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1–1.5 mm long; eventually visible between lemmas.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–4 mm long; 0.8–0.9 length of upper glume; chartaceous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume surface smooth, or asperulous. Lower glume apex acute. Upper glume lanceolate; 3–4.5 mm long; 0.7–0.8 length of adjacent fertile lemma; chartaceous; without keels; 3 -veined. Upper glume surface smooth, or asperulous. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 4–6 mm long; chartaceous; without keel; 5 -veined. Lemma lateral veins obscure. Lemma surface smooth, or scaberulous; glabrous, or puberulous, or pubescent. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn flexuous; 4–12 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3; 2–3 mm long. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, and southwest USA.

NOTES Poeae. Fl Pac NW 1994.

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