Trisetum montanum

HABIT Perennial; caespitose. Culms erect, or geniculately ascending; 50–100 cm long. Culm-internodes distally glabrous. Leaf-sheaths smooth, or scaberulous; glabrous on surface, or puberulous. Ligule an eciliate membrane; 2–3 mm long; erose; truncate. Leaf-blades 10–20 cm long; 2–4 mm wide. Leaf-blade surface scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear; 10–15 cm long; 1–2.5 cm wide. Primary panicle branches appressed; bearing spikelets almost to the base. Panicle axis scaberulous. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose. Floret callus pubescent. Floret callus hairs 1 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma; shiny. Lower glume lanceolate; 2.5 mm long; 0.66 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume elliptic; 4 mm long; 0.8 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; 5 mm long; membranous; keeled; 5 -veined. Lemma surface scaberulous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.66 way up back of lemma; geniculate; spreading; 5 mm long overall; with twisted column. Palea gaping; hyaline. Rhachilla extension pilose.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform. Endosperm soft.

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

NOTES Aveneae. N Amer Fl 1994.

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