Trisetum nancaguense

HABIT Perennial; caespitose. Culms 40–75 cm long; 2–4 -noded. Culm-internodes distally glabrous. Culm-nodes glabrous, or pubescent. Leaf-sheaths 15–20 cm long; mostly shorter than adjacent culm internode; pubescent. Ligule an eciliate membrane; 2–3 mm long; erose; truncate. Leaf-blades 4–15 cm long; 2–5 mm wide. Leaf-blade surface puberulous (beneath), or pilose (above); hairy on both sides. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear, or lanceolate; continuous, or interrupted; 6.5–9 cm long; 0.8–2 cm wide. Panicle axis scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 2–3.5 mm long; pubescent.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets oblong; laterally compressed; 5.5–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1 mm long; pilose. Floret callus pubescent; obtuse.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma; shiny; gaping. Lower glume linear; 3.5–6 mm long; 0.66–0.75 length of upper glume; membranous; much thinner on margins; mid-green and purple; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume apex acute; muticous, or awned; 1 -awned. Lower glume awn 0.5–1 mm long. Upper glume lanceolate; 5.3–7.6 mm long; 0.8–0.9 length of adjacent fertile lemma; membranous; with hyaline margins; mid-green and purple; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute; awned; 1 -awned. Upper glume awn 0.5–1 mm long.

FLORETS Fertile lemma elliptic; 6.5–7.5 mm long; membranous; much thinner above; much thinner on margins; mid-green and purple; tipped with last colour; shiny; keeled; 5 -veined. Lemma surface hirsute. Lemma apex dentate; 2 -fid; awned; 3 -awned. Principal lemma awn dorsal; arising 0.66 way up back of lemma; geniculate; 6–9 mm long overall; with a straight or slightly twisted column. Lateral lemma awns arising on apex of lobes; exserted. Palea gaping; 4–5 mm long; hyaline. Palea keels scaberulous. Palea apex with excurrent keel veins.

FLOWER Lodicules 2; 0.8–1 mm long. Anthers 3; 1.5 mm long; yellow. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; 2.5–3 mm long; glabrous. Endosperm liquid.

DISTRIBUTION South America: southern South America.

NOTES Aveneae. Finot et al 2006.

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