Digitaria argillacea

HABIT Annual. Culms erect; 30–60 cm long. Culm-nodes bearded. Ligule a ciliolate membrane. Leaf-blades 15–25 cm long; 3–4 mm wide; flaccid. Leaf-blade surface scaberulous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–4; paired, or digitate; erect; flexuous; unilateral; 10–15 cm long. Rhachis wingless; angular; 0.4–0.5 mm wide; puberulous on surface.

Spikelets in threes. Fertile spikelets pedicelled; 3 in the cluster. Pedicels unequal; 6–12 mm long; glabrous, or bearing a few hairs.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; dorsally compressed; acute; 1.8–2 mm long; falling entire.

GLUMES Glumes one the lower absent or obscure; shorter than spikelet; thinner than fertile lemma. Upper glume lanceolate; 0.75 length of spikelet; membranous; without keels; 3 -veined. Upper glume surface pubescent and setose; hairy on veins (setose). Upper glume hairs red. Upper glume apex acute.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 1 length of spikelet; membranous; 7 -veined; pubescent and setose; bearing red hairs; acute. Fertile lemma ovate; 1.8–2 mm long; cartilaginous; much thinner on margins; black; shiny; without keel. Lemma margins flat; covering most of palea. Lemma apex acute. Palea cartilaginous.

DISTRIBUTION Africa: west tropical, west-central tropical, and northeast tropical. North America: Mexico. South America: Mesoamericana, Caribbean, and western South America.

NOTES Paniceae. FTA.

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