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.

Deyeuxia mandoniana

HABIT Perennial. Rhizomes elongated. Culms erect; 46–120 cm long. Culm-internodes smooth, or antrorsely scabrous. Leaf-sheaths smooth, or antrorsely scabrous. Ligule an eciliate membrane, or a ciliolate membrane; 2–12 mm long; obtuse, or acute, or acuminate. Leaf-blades flat, or convolute; 30–60 cm long; 3.3–3.6 mm wide. Leaf-blade venation with subepidermal sclerenchyma attached to veins above and below; without layer of subepidermal sclerenchyma masking vein striation. Leaf-blade surface scabrous; rough on both sides. Leaf-blade apex acute, or acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; linear; nodding; 24–52 cm long; 2–5 cm wide. Primary panicle branches ascending, or drooping; 10–16 cm long. Panicle axis smooth, or scaberulous. Panicle branches smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 1.2–6.6 mm long; smooth, or scaberulous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; laterally compressed; 6.2–7.8 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent. Floret callus hairs 0.8–1.2 mm long; 0.15–0.3 length of lemma.

GLUMES Glumes persistent; similar; reaching apex of florets; firmer than fertile lemma. Lower glume lanceolate; 6.2–7.8 mm long; 1.05 length of upper glume; membranous; purple; 1-keeled; 1 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent. Lower glume surface scabrous; rough above. Lower glume apex acute, or acuminate. Upper glume lanceolate; 5.8–7.6 mm long; membranous; purple; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume surface scabrous; rough above. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 5–6.2 mm long; membranous; without keel; 5 -veined. Lemma surface scabrous; rough generally, or on veins. Lemma apex dentate; 2–4 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.33–0.5 way up back of lemma; geniculate; 5–7.2 mm long overall; clearly exserted from spikelet; with a straight or slightly twisted column. Palea 4–5 mm long. Rhachilla extension 1.6–2.4 mm long; villous; with 3.2–4.2 mm long hairs.

FLOWER Lodicules 2. Anthers 3; linear; 2.2–2.6 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform. Disseminule comprising a floret.

DISTRIBUTION South America: western South America.

NOTES Aveneae. Villav 1996.

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