Nassella tucumana

HABIT Perennial; caespitose; clumped loosely. Culms erect; slender; 60–100 cm long; 1–1.5 mm diam.; 3 -noded. Culm-internodes smooth, or scaberulous; distally glabrous. Leaf-sheaths mostly shorter than adjacent culm internode; striately veined; antrorsely scabrous. Ligule an eciliate membrane. Leaf-blades flat, or convolute; 25–40 cm long; 2–5 mm wide; flaccid. Leaf-blade surface scabrous; glabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; nodding; 15–30 cm long. Primary panicle branches ascending, or spreading; 2–3 -nate; 3–10 cm long. Panicle branches capillary.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels filiform; glabrous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; subterete; 4–5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus brief; pubescent; acute.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 4–4.5 mm long; 1.1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein scabrous. Lower glume apex acuminate. Upper glume lanceolate; 3.5–4 mm long; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acuminate.

FLORETS Fertile lemma obovate; subterete; 2.5–3 mm long; coriaceous; without keel; 5 -veined. Lemma midvein ciliolate. Lemma surface punctate; glabrous, or puberulous. Lemma margins convolute; covering most of palea. Lemma apex awned; 1 -awned. Principal lemma awn bigeniculate; 15 mm long overall; with twisted column. Column of lemma awn puberulous. Palea present.

FLOWER Anthers 3; 0.5 mm long; retained within floret.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: southern South America.

NOTES Stipeae. Parodi 1997.

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