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Descriptions

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

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

Erioneuron avenaceum

HABIT Perennial; caespitose. Stolons absent. Culms 15–60 cm long. Leaves mostly basal. Ligule a fringe of hairs. Leaf-blades 2–12 cm long; 1–3 mm wide. Leaf-blade surface pilose; sparsely hairy. Leaf-blade margins cartilaginous. Leaf-blade apex abruptly acute; apiculate.

INFLORESCENCE Inflorescence a panicle.

Panicle capitate; oblong; 2–6 cm long.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels linear.

FERTILE SPIKELETS Spikelets comprising 4–8 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose.

GLUMES Glumes persistent; similar; reaching apex of florets, or shorter than spikelet; shiny. Lower glume ovate; 4–6 mm long; 1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume ovate; 4–6 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acuminate.

FLORETS Fertile lemma ovate; 4–6 mm long; membranous; without keel; 3 -veined. Lemma surface pilose; hairy below. Lemma margins ciliate; hairy all along. Lemma apex lobed; 2 -fid; incised 0.4–0.5 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; 1–3 mm long overall. Palea 2 -veined. Palea keels ciliolate. Palea surface pilose; hairy on back. Apical sterile florets resembling fertile though underdeveloped.

FRUIT Caryopsis with adherent pericarp; ovoid; laterally compressed; smooth (translucent). Embryo 0.5 length of caryopsis; projecting below grain.

CLEISTOGENES AND VIVIPARY Cleistogenes present; in lower sheaths.

DISTRIBUTION North America: southwest USA, south-central USA, and Mexico. South America: western South America and southern South America.

NOTES Eragrostideae. Gould.

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