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.

Digitaria atra

HABIT Perennial; caespitose. Rhizomes short. Culms erect; slender; 30–38 cm long; 0.8–1 mm diam.; 2–3 -noded. Culm-internodes distally pubescent, or pilose. Lateral branches lacking. Leaf-sheaths 6.5–10.5 cm long; mostly shorter than adjacent culm internode; striately veined; hirsute; with tubercle-based hairs. Ligule an eciliate membrane; 1–1.5 mm long; truncate. Leaf-blades flexuous; 6–25 cm long; 1.5–2 mm wide. Leaf-blade surface hirsute; hairy on both sides; with tubercle-based hairs. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle hirsute above.

Racemes 1; single; unilateral; 6–7 cm long. Rhachis angular; 0.5 mm wide; hirsute on surface.

Spikelets solitary, or in pairs (in middle of raceme). Fertile spikelets pedicelled. Pedicels 1–2.5 mm long; pubescent; hairy at tip; with 0.2–0.3 mm long hairs.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acuminate; 2.5 mm long; 1.2 mm wide; falling entire.

GLUMES Glumes one the lower absent or obscure. Upper glume elliptic; 2.2–2.3 mm long; 1 length of spikelet; membranous; without keels; 3(–5) -veined. Upper glume surface pubescent; hairy between veins; with clavate hairs. Upper glume apex obtuse.

FLORETS Basal sterile florets barren; with palea. Lemma of lower sterile floret elliptic; 2 mm long; 1 length of spikelet; cartilaginous; much thinner on margins; yellow; 5 -veined; glabrous, or pubescent; hairy at base; with clavate hairs; acute. Palea of lower sterile floret 0.4–0.5 mm long; smooth, or pubescent (below). Fertile lemma elliptic; 2 mm long; cartilaginous; much thinner on margins; black; without keel. Lemma surface striate; puberulous; hairy at base; hairy in lines (two); with clavate hairs. Lemma margins flat; covering most of palea. Lemma apex acute. Palea cartilaginous.

FLOWER Lodicules 2; 0.2 mm long; membranous; truncate. Anthers 3.

FRUIT Caryopsis with adherent pericarp; ovoid; 1.4 mm long. Embryo 0.33 length of caryopsis. Hilum punctiform.

DISTRIBUTION South America: northern South America.

NOTES Paniceae. Vega & Rugolo 2002.

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