GrassBase - The Online World Grass Flora

Descriptions

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

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

Tridentopsis

HABIT Perennial. Culms erect; 20–62.5–100 cm long. Ligule an eciliate membrane (1), or a ciliate membrane (1).

INFLORESCENCE Inflorescence a panicle.

Panicle open (1), or contracted (1).

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 5–11 fertile florets, or 12 fertile florets (1); with diminished florets at the apex. Spikelets oblong (1), or ovate (1); laterally compressed; 3–7.75–13 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite. Floret callus pubescent.

GLUMES Glumes persistent; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 0.9–0.925–1 length of upper glume; membranous; 1-keeled; 1 -veined, or 2–7 -veined (1). Lower glume lateral veins absent (1), or distinct (1). Lower glume surface without pits. Lower glume apex acute, or acuminate (1); mucronate. Upper glume lanceolate; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined, or 2–7 -veined (1). Upper glume apex acute, or acuminate (1).

FLORETS Fertile lemma elliptic; chartaceous; without keel; wingless; 3 -veined. Lemma midvein ciliate (1), or pubescent (1). Lemma lateral veins excurrent (1), or extending close to apex (1). Lemma surface unwrinkled; without grooves. Lemma margins ciliate (1), or pubescent (1). Lemma apex entire, or dentate; 2 -fid; emarginate, or obtuse; muticous (1), or mucronate (1). Palea 0.66–0.8025–0.9 length of lemma. Palea keels smooth, or scaberulous (1). Palea surface glabrous (1), or pubescent (1). Apical sterile florets resembling fertile though underdeveloped.

FRUIT Caryopsis with adherent pericarp; oblong (1/1); dorsally compressed (1/1); reticulate (1/1).

DISTRIBUTION North America, or South America (1).

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