GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Tridens congestus

HABIT Perennial; caespitose. Rhizomes elongated. Culms 30–75 cm long. Lateral branches lacking. Leaf-sheaths without keel. Ligule a ciliate membrane; 0.2–0.5 mm long. Leaf-blades 1.5–5 mm wide. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; linear, or oblong; 5–8(–10) cm long; 1.2–2.5 cm wide. Primary panicle branches appressed; 0.5–3 cm long. Panicle axis glabrous. Panicle branches glabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 5–11 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–10 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume oblong; 2.5–3 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex obtuse, or acute. Upper glume oblong; 3–4 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex obtuse, or acute.

FLORETS Fertile lemma elliptic; 3–4 mm long; membranous; without keel; 3 -veined. Lemma midvein pubescent; hairy below (0.33–0.5 of length). Lemma lateral veins extending close to apex. Lemma margins pubescent; hairy below. Lemma apex emarginate; mucronate. Palea bowed outwards; 2.5–3 mm long; 0.75–0.85 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FRUIT Caryopsis with adherent pericarp; oblong. Embryo not projecting.

DISTRIBUTION North America: south-central USA.

NOTES Eragrostideae. Gr Texas 1993.

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