Trisetum glomeratum

HABIT Perennial; caespitose; clumped densely. Culms erect; 40–90 cm long. Leaf-sheaths 4–12 cm long; glabrous on surface, or pubescent. Ligule an eciliate membrane; 2–3 mm long; lacerate. Leaf-blades flat, or involute; 10–25 cm long; 2–4(–6) mm wide; coriaceous; stiff. Leaf-blade surface glabrous, or pubescent. Leaf-blade apex pungent.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted, or spiciform; linear; interrupted; 12–20 cm long; 1 cm wide. Panicle axis puberulous. Panicle branches pubescent.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 4–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pubescent. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet, or reaching apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume linear; 4–5 mm long; 1 length of upper glume; hyaline; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume surface asperulous. Lower glume margins ciliolate. Lower glume apex acuminate. Upper glume lanceolate; 4–5 mm long; 1 length of adjacent fertile lemma; hyaline; 1-keeled; 3 -veined. Upper glume surface asperulous. Upper glume margins ciliolate. Upper glume apex acuminate.

FLORETS Fertile lemma elliptic; 4–5 mm long; membranous; keeled; 5 -veined. Lemma lateral veins obscure. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.75–0.8 way up back of lemma; geniculate; 2–5 mm long overall; with twisted column. Palea gaping; 4–5 mm long; hyaline. Palea keels scaberulous.

FLOWER Anthers 3. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; oblong; 2.5–3 mm long; dark brown, or red. Hilum punctiform.

DISTRIBUTION Pacific: north-central.

NOTES Aveneae. Wagner 1993.

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