Nassella viridula

HABIT Perennial; caespitose. Culms 50–110 cm long. Culm-internodes distally glabrous, or pubescent. Leaf-sheaths glabrous on surface, or puberulous; outer margin hairy. Ligule an eciliate membrane; 0.5–1.5(–3) mm long; glabrous on abaxial surface, or pubescent on abaxial surface; obtuse. Collar pilose. Leaf-blades involute; 3–6 mm wide.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear, or lanceolate; 10–26 cm long. Primary panicle branches appressed.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 9–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus evident; 0.5 mm long; pubescent; acute.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma. Lower glume lanceolate; 9–12 mm long; 1 length of upper glume; membranous; without keels; 5 -veined. Lower glume apex acuminate. Upper glume lanceolate; 9–12 mm long; 2 length of adjacent fertile lemma; membranous; without keels; 3 -veined. Upper glume apex acuminate.

FLORETS Fertile lemma elliptic; subterete; 5–6 mm long; coriaceous; without keel. Lemma surface pubescent; hairy all along. Lemma margins convolute; covering most of palea. Lemma apex awned; 1 -awned. Principal lemma awn bigeniculate; 25–35 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 2 mm long; 0 -veined; without keels.

FLOWER Lodicules 2; 1.2–1.5 mm long. Anthers 3; 2.5–3 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

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

NOTES Stipeae. Fl Pac NW 1993.

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