Trisetum ligulatum

HABIT Perennial. Rhizomes short. Culms 13–30 cm long; 1–3 -noded. Leaf-sheaths longer than adjacent culm internode; pubescent. Ligule an eciliate membrane; 3–4 mm long; pilose on abaxial surface; truncate. Leaf-blades flat, or conduplicate; 5–20 cm long; 1–2.5 mm wide. Leaf-blade surface pubescent.

INFLORESCENCE Inflorescence a panicle. Peduncle pilose above.

Panicle spiciform; linear; 5–9 cm long; 0.5–1.2 cm wide. Panicle axis pubescent.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 5–6.5 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; sparsely hairy; with 0.5 mm long hairs. Floret callus pubescent. Floret callus hairs 0.5 mm long.

GLUMES Glumes persistent; similar; reaching apex of florets; thinner than fertile lemma; shiny; gaping. Lower glume lanceolate; 3.8–6 mm long; 0.8–0.9 length of upper glume; membranous; mid-green, or purple; 1-keeled; 3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume lanceolate; 4.5–6.5 mm long; 1 length of adjacent fertile lemma; membranous; mid-green, or purple; 1-keeled; 3(–5) -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 4.3–6.5 mm long; membranous; shiny; keeled; 5 -veined. Lemma lateral veins excurrent. Lemma surface scabrous; glabrous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.66 way up back of lemma; curved; 2–3.5 mm long overall. Palea gaping; 4.3–6.5 mm long; hyaline. Palea keels scabrous.

FLOWER Lodicules 2. Anthers 3; 1.5 mm long. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION North America: Mexico.

NOTES Aveneae. Finot & Zuloaga 2005.

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