Festuca idahoensis

HABIT Perennial; caespitose; clumped densely. Culms erect; 40–100 cm long. Leaves mostly basal. Leaf-sheaths smooth, or scaberulous. Ligule an eciliate membrane; 0.3–0.6 mm long. Leaf-blades filiform; conduplicate; 5–10 cm long; 0.5–1 mm wide. Leaf-blade surface scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; (5–)7–15(–20) cm long. Primary panicle branches appressed, or ascending.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4–8 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 10–13 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; 2.5–5 mm long; 0.5–0.66 length of upper glume; membranous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate, or elliptic; 4–6.5 mm long; 0.9 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 4.5–7.5 mm long; chartaceous; without keel; 5 -veined. Lemma surface smooth, or scaberulous. Lemma apex acute; awned; 1 -awned. Principal lemma awn 2–5 mm long overall. Palea 1 length of lemma; 2 -veined. Palea keels scaberulous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3; 2.5–4 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: northwest USA and southwest USA.

NOTES Poeae. Fl Pac NW 1993.

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