Stipa lettermanii

HABIT Perennial; caespitose; clumped densely. Culms 20–60 cm long. Culm-internodes smooth; distally glabrous. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 0.3–0.8 mm long; truncate. Collar glabrous. Leaf-blades filiform; involute; 1–1.5 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; 5–15 cm long. Primary panicle branches appressed.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 6–9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5–1 mm long; pubescent; acute.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 1 length of upper glume; membranous; without keels; 3 -veined. Lower glume apex acuminate. Upper glume lanceolate; 6–9 mm long; hyaline; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate; subterete; 4.5–6 mm long; 1 mm wide; membranous; without keel; 5 -veined. Lemma surface pubescent. Lemma margins flat; covering most of palea. Lemma apex emarginate; awned; 1 -awned. Principal lemma awn bigeniculate; 15–20 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 3.5 mm long; 0.8 length of lemma; 2 -veined; without keels. Palea surface pubescent.

FLOWER Lodicules 3; 1.5 mm long. Anthers 3; 2.5 mm long. Stigmas 2. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION North America: northwest USA, southwest USA, and south-central USA.

NOTES Stipeae. Fl Pac NW 1994.

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