Trisetum flavescens

HABIT Perennial; caespitose. Butt sheaths pilose. Culms erect, or geniculately ascending; 20–80(–100) cm long; 2–5 -noded. Ligule an eciliate membrane; 0.3–1.1 mm long. Leaf-blades 3.5–12 cm long; 2–5 mm wide. Leaf-blade surface glabrous, or pubescent. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; elliptic; 7–15 cm long; 1.5–7 cm wide. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 1–4 mm long; scaberulous.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets oblong, or cuneate; laterally compressed; 5–7(–8) mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pubescent. Floret callus pubescent.

GLUMES Glumes persistent; dissimilar; shorter than spikelet; thinner than fertile lemma; shiny; gaping. Lower glume lanceolate; 2.5–4.7 mm long; 0.66–0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume elliptic; 4.3–6.5 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scaberulous. Upper glume apex acuminate.

FLORETS Fertile lemma obovate; 4.4–6.3 mm long; chartaceous; much thinner above; much thinner on margins; yellow; shiny; keeled; 5 -veined. Lemma surface asperulous; rough above. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5–0.66 way up back of lemma; geniculate; 5–9 mm long overall; with twisted column. Palea gaping; hyaline. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 1.3–2.5(–2.8) mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; linear. Hilum punctiform.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Africa: north and Macaronesia. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, and western Asia. Asia-tropical: India and Papuasia. Australasia: Australia. Pacific: north-central. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, and southwest USA. South America: southern South America.

NOTES Aveneae. TAC.

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