Trisetum spicatum

HABIT Perennial; caespitose. Rhizomes elongated. Culms erect, or geniculately ascending; 8–50 cm long; 2–5 -noded. Leaf-sheaths glabrous on surface, or pubescent. Ligule an eciliate membrane. Leaf-blades flat, or involute; 4–10 cm long; 1–3.5 mm wide. Leaf-blade surface glabrous to hirsute. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle. Peduncle pubescent above.

Panicle spiciform; linear, or ovate; 1.5–7.5 cm long; 1–2 cm wide. Panicle axis puberulous. Panicle branches puberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 4–7.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pubescent. Floret callus pubescent.

GLUMES Glumes persistent; similar; reaching apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume elliptic; 3.5–5 mm long; 0.75–0.9 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent, or obscure. Lower glume apex acute. Upper glume elliptic; 4–6.5 mm long; 1–1.2 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 4–5.5 mm long; membranous; much thinner above; much thinner on margins; shiny; keeled; 5 -veined. Lemma surface glabrous, or puberulous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.66 way up back of lemma; geniculate; reflexed; 2.5–6.5 mm long overall; with twisted column. Palea gaping; hyaline. Palea keels scaberulous.

FLOWER Anthers 3. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Asia-temperate: Siberia, Soviet far east, Soviet Middle Asia, Caucasus, western Asia, China, Mongolia, and eastern Asia. Asia-tropical: India, Malesia, and Papuasia. Australasia: Australia and New Zealand. North America: Subarctic, western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Mesoamericana, Caribbean, western South America, and southern South America. Antarctic: Subantarctic islands.

NOTES Aveneae. Fl Pak 1993.

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