Tridens riograndensis

HABIT Perennial; caespitose. Rhizomes short. Basal innovations intravaginal. Culms erect; 50–60 cm long. Culm-nodes glabrous. Lateral branches lacking. Leaves mostly basal. Ligule a fringe of hairs; 1 mm long. Leaf-blades flat, or convolute; 9–30 cm long; 4–6 mm wide. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform; linear; continuous, or interrupted; 6–8 cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 6–7 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus glabrous; obtuse.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume oblong; 2.5 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse; mucronate. Upper glume oblong; 3 mm long; 0.75–0.85 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex obtuse; mucronate.

FLORETS Fertile lemma lanceolate; 3.5–4 mm long; membranous; without keel; 3 -veined. Lemma midvein ciliate. Lemma lateral veins excurrent. Lemma margins ciliate. Lemma apex dentate; 2 -fid; awned; 3 -awned. Principal lemma awn from a sinus; 1.2–1.8 mm long overall. Lateral lemma awns arising on outer edge of lobes; 0.3–1 mm long. Palea with flaps as wide as body; 2.6–3 mm long; 2 -veined; 2-keeled. Palea apex emarginate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; cuneate; fleshy; glabrous. Anthers 3; 0.5–0.6 mm long.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 1–1.2 mm long; light brown.

DISTRIBUTION South America: Brazil.

NOTES Eragrostideae. Acedo & Llamas 2005.

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