Cenchrus riparius (Hochst. ex A.Rich.) Morrone

Habit

Perennial; mat forming. Rhizomes elongated. Stolons present. Culms decumbent; 10-150 cm long. Ligule a fringe of hairs. Leaf-blades flat, or conduplicate; 4-30 cm long; 2-10 mm wide.

Inflorescences

Inflorescence a panicle; embraced at base by subtending leaf. Panicle spiciform; linear; 2-15 cm long. Primary panicle branches accrescent to a central axis; with sessile scars on axis. Panicle axis angular; scaberulous; glabrous; bearing deciduous spikelet clusters. Spikelets subtended by an involucre. Fertile spikelets sessile; 1-2 in the cluster. Involucre composed of bristles; oblong; 3-6 mm long; base obtuse. Involucral bristles deciduous with the fertile spikelets; numerous; with one conspicuously longer bristle; 7-15 mm long; terete; flexible; glabrous.

Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; acute, or acuminate; 6-10 mm long; falling entire; deciduous with accessory branch structures.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; acute, or acuminate; 6-10 mm long; falling entire; deciduous with accessory branch structures.

Glume

Glumes dissimilar; shorter than spikelet; thinner than fertile lemma. Lower glume oblate; 0.05 length of spikelet; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume apex truncate. Upper glume ovate; 0.25-0.33 length of spikelet; hyaline; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume apex obtuse, or acute.

Florets

Basal sterile florets male, or barren; with palea. Lemma of lower sterile floret ovate; 0.8-1 length of spikelet; membranous; 5-7 -veined; acute. Fertile lemma ovate; 6-10 mm long; membranous; without keel; 5-7 -veined. Lemma margins flat. Lemma apex acute. Palea membranous.

Flowers

Lodicules absent. Anthers 3; 3 mm long; anther tip smooth. Styles connate below.

Distribution

Africa: northeast tropical and east tropical.

Reference

Paniceae. FTEA.

Gramineae, W. D. Clayton, S. M. Phillips & S. A. Renvoize. Flora of Tropical East Africa. 1974

Habit

Perennial, with long stout stolons and rhizomes forming a low matted sward, or with tall ascending culms; culms 10–150 cm. high, ascending from a creeping base.

Leaves

Leaf-blades linear, 4–30 cm. long, 2–10 mm. wide, flat or folded.

Inflorescences

Panicle linear, 2–15 cm. long, often enclosed below by the uppermost sheath; rhachis with shallow angular ribs below the flat stumpless scars, scaberulous; involucre enclosing 1–2 subsessile spikelets, without a distinct stipe; bristles glabrous, the longest 7–15 mm.

Spikelets

Spikelets narrowly lanceolate, 6–10 mm. long, acute to acuminate; lower glume minute, up to 0.5 mm., upper glume 1/4–1/3 the length of the spikelet; lower lemma from 4/5 to as long as the spikelet, ♂ or barren, the upper similar in texture.

Habitat

In swamps; also semi-cultivated around habitations, being gathered and burnt to yield salt from the ashes; 1400–2600 m.

Distribution

K3 K4 T2 T7 U3