Festuca thurberi

HABIT Perennial; caespitose; clumped densely. Culms 60–90 cm long. Lateral branches lacking. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 2–4 mm long. Leaf-blades erect; conduplicate; 1–2 mm wide; coriaceous. Leaf-blade surface scabrous; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; ovate; 10–15 cm long; with spikelets clustered towards branch tips. Primary panicle branches ascending, or spreading; 1 -nate.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–6 fertile florets; with diminished florets at the apex. Spikelets elliptic; laterally compressed; 10–17 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume elliptic; 4 mm long; 0.75 length of upper glume; chartaceous; without keels; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume elliptic; 5 mm long; 0.66 length of adjacent fertile lemma; chartaceous; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate; 7–8 mm long; chartaceous; without keel; 5 -veined. Lemma lateral veins obscure. Lemma apex acute, or cuspidate; muticous. Palea 1 length of lemma; 2 -veined. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2. Anthers 3. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: northwest USA, southwest USA, and Mexico.

NOTES Poeae. Man US Gr 1994.

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