Digitaria didactyla Willd.

Morphology General Habit

Perennial; mat forming. Rhizomes elongated; knotty. Stolons present. Culms prostrate; 15-30 cm long; rooting from lower nodes. Culm-nodes brown; glabrous. Leaf-sheaths smooth, or scaberulous; glabrous on surface. Ligule an eciliate membrane; 0.8 mm long. Leaf-blades 3-6(-10) cm long; 3-6 mm wide; glaucous. Leaf-blade surface smooth; glabrous. Leaf-blade margins scaberulous.

Morphology Reproductive morphology Inflorescences

Inflorescence composed of racemes. Racemes 2-3(-4); paired, or digitate; unilateral; 3-10 cm long. Rhachis wingless, or narrowly winged; with sharp-edged midrib; angular; 0.6 mm wide; smooth on surface; scaberulous on margins. Spikelets in pairs. Fertile spikelets pedicelled; 2 in the cluster. Pedicels terete, or angular; unequal; 0.5-2.5 mm long; scaberulous; tip widened.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; (2-)2.2-2.7 mm long; falling entire.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate, or oblong; dorsally compressed; (2-)2.2-2.7 mm long; falling entire.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes two; dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; 0.1 length of spikelet; membranous; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume apex truncate. Upper glume ovate; 0.33-0.5 length of spikelet; membranous; without keels; 3 -veined. Upper glume surface pubescent. Upper glume apex acute.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of spikelet; membranous; 7 -veined; smooth, or scaberulous; rough on veins; pubescent; acute. Fertile lemma lanceolate; 2-2.7 mm long; cartilaginous; much thinner on margins; yellow, or light brown; without keel. Lemma margins flat; covering most of palea. Lemma apex acute. Palea cartilaginous.

Distribution

Africa: southern tropical, south, and western Indian ocean. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern. South America: northern South America.

Reference

Paniceae. FZ.

Gramineae, W. D. Clayton. Flora Zambesiaca 10:3. 1989

Morphology General Habit

A loosely caespitose perennial with a knotty much branched rhizome.

Morphology Stem

Stems prostrate or creeping and then sometimes branching, nodes dark and glabrous.

Morphology Leaves Leaf sheaths

Leaf sheaths glabrous, smooth to scaberulous.

Morphology Leaves Ligules

Ligule c. 0.8 mm. long, rimlike, glabrous.

Morphology Leaves Leaf lamina

Leaf lamina 3–6(10) × 0.3–0.6 cm., linear, flat, (sub)glabrous and smooth on both surfaces, often glaucous, scaberulous along the margins.

Morphology Reproductive morphology Inflorescences

Inflorescence composed of 2–3(4) racemes, 3–10 cm. long, digitately on top of the peduncle.

Morphology Leaves Rachis

Rhachis triquetrous, winged, up to 0.6 mm. wide, smooth with scaberulous margins.

Morphology Reproductive morphology Flowers Pedicel

Pedicels 2-nate, 0.5–2.5 mm. long, subterete to triangular, scaberulous, slightly widened at the apex.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets (2.0)2.2–2.7 mm. long, oblong to lanceolate.

Morphology Reproductive morphology Inflorescences Bracts Glume

Superior glume 1/2–1/3 of the spikelet, triangular, 3-nerved, appressed hairy, hairs fine, whitish. Inferior glume short, ovate to triangular, often truncate.

Inferior

Inferior lemma as long as the spikelet, lanceolate, 7-nerved, nerves smooth to scaberulous, appressed hairy. Inferior glume short, ovate to triangular, often truncate.

Morphology Reproductive morphology Inflorescences Bracts Lemma

Superior lemma as long as the spikelet, lanceolate, acute, pale yellow to pale brown, sometimes purplish tinged. Inferior lemma as long as the spikelet, lanceolate, 7-nerved, nerves smooth to scaberulous, appressed hairy.

Superior

Superior lemma as long as the spikelet, lanceolate, acute, pale yellow to pale brown, sometimes purplish tinged. Superior glume 1/2–1/3 of the spikelet, triangular, 3-nerved, appressed hairy, hairs fine, whitish.