Trisetum macbridei

HABIT Perennial; caespitose. Culms erect; 20–40 cm long. Culm-internodes distally glabrous. Leaves mostly basal. Leaf-sheaths puberulous. Ligule an eciliate membrane; 1–2 mm long; pubescent on abaxial surface. Leaf-blades 4–10 cm long; 1–6 mm wide. Leaf-blade surface puberulous.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; interrupted; 7–8 cm long. Panicle axis scaberulous. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels scaberulous.

FERTILE SPIKELETS Spikelets comprising 2 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; pubescent; with 1 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; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 1.1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume lateral veins absent. Upper glume apex acute.

FLORETS Fertile lemma oblong; 5 mm long; membranous; shiny; keeled; 5 -veined. Lemma surface scaberulous. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5–0.6 way up back of lemma; geniculate; 5–6 mm long overall; with twisted column. Palea gaping; 3 mm long; hyaline. Palea keels ciliolate.

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION South America: northern South America and western South America.

NOTES Aveneae. Hitchcock 1995.

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