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.

Digitaria xanthotricha

HABIT Annual. Culms erect, or geniculately ascending; slender; 60–100 cm long; 3–4 -noded. Culm-internodes unequal, the upper longer; terete; distally glabrous. Lateral branches lacking. Leaf-sheaths tight; mostly shorter than adjacent culm internode; glabrous on surface, or hirsute; with tubercle-based hairs. Ligule a ciliolate membrane; brown. Leaf-blades 2.5–5 cm long; 3–5 mm wide. Leaf-blade surface smooth; glabrous. Leaf-blade margins cartilaginous; scaberulous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–4; digitate; unilateral; 7–18 cm long. Rhachis wingless; angular; 0.4–0.5 mm wide; scabrous on margins; pubescent on margins. Spikelet packing contiguous, or lax.

Spikelets in pairs, or in threes, or clustered at each node. Fertile spikelets pedicelled; 2–4 in the cluster. Pedicels filiform; unequal; 0.5–3 mm long; scabrous; ciliate.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic; dorsally compressed; acute; 2.5 mm long; 0.8 mm wide; falling entire.

GLUMES Glumes one the lower absent or obscure; shorter than spikelet; thinner than fertile lemma. Upper glume lanceolate; 0.9 length of spikelet; narrower than lemma; membranous; without keels; 3 -veined. Upper glume surface pubescent; hairy between veins. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret elliptic; 1 length of spikelet; membranous; 3 -veined; with marginal tufts of hair and with a transverse fringe of hair; 2 hair tufts in all (and fringe); bearing yellow hairs; bearing hairs 1 mm long; acute. Fertile lemma lanceolate; 2.5 mm long; cartilaginous; much thinner on margins; pallid; without keel; 3 -veined. Lemma surface punctate. Lemma margins flat; covering most of palea. Lemma apex acute. Palea cartilaginous.

FLOWER Anthers 3; 1.5 mm long.

FRUIT Caryopsis with adherent pericarp; oblong; plano-convex; 2 mm long. Embryo 0.4–0.5 length of caryopsis.

DISTRIBUTION Africa: northeast tropical.

NOTES Paniceae. FTA 1997.

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