Melinis ambigua Hack.

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

Morphology General Habit

Caespitose or rarely tufted perennial.

Morphology Culms

Culms (30)60–120(150) cm. high, erect or rarely geniculately ascending.

Morphology Leaves Leaf lamina

Leaf laminae (3.5)5–30 cm. long, 2–8(11) mm. wide, flat or involute.

Morphology Reproductive morphology Inflorescences

Panicle 9–25 cm. long, narrowly ovate.

Morphology Reproductive morphology Flowers Pedicel

Pedicels with a few long hairs.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets (2)2.4–4.4(5.2) mm. long, narrowly ovate.

Morphology Reproductive morphology Inflorescences Bracts Glume

Inferior glume 0.4–1.2 mm. long, ovate, 0–1-nerved, inserted close to the superior; superior glume 7-nerved, usually hairy, emarginate to bilobed with an awn (0.1)0.5–6.8(8.3) mm. long.

Morphology Reproductive morphology Flowers Florets

Inferior floret male or barren, its lemma 5-nerved with an awn (0.3)2–13(14) mm. long, equalling the superior glume; palea absent or when present scabrous on its keels.

Note

M. ambigua, M. minutiflora, M. tenuissima, M. effusa and M. macrochaeta form a group of similar species with rare intermediate forms occurring between neighbouring species. The weakest delimitation is between M. minutiflora on the one side and M. ambigua, M. effusa and M. tenuissima on the other. M. ambigua is a very variable species. Subsp. ambigua and subsp. longicauda differ in spikelet morphology and habit with many intermediate forms occurring. Forms of subsp. longicauda may approach M. longiseta, but the nervation and hairiness of the superior glume are reliable characters for identification. Rare specimens with the keels of the inferior palea ciliate, possibly introgression products from M. repens, have been described as Rhynchelytrum bequaertii.

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

Morphology General Habit

Tufted or geniculately ascending perennial; culms 60–120 cm. high.

Morphology Leaves

Leaf-blades flat or occasionally involute, 5–20 cm. long, 2–10 mm. wide, glabrous to softly pilose, ± sticky.

Morphology Reproductive morphology Inflorescences

Panicle oblong, 5–20 cm. long; pedicels puberulous, with or without long hairs near the tip.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets narrowly oblong, (2–)2.5–4 mm. long, silky pilose from long pink, purple or silvery hairs (commonly tubercle-based) exceeding the tip by 1–4 mm.; lower glume a little oblong scale 0.5–1 mm. long; upper glume straight on the back, 7-nerved, these sometimes forming shallow ribs, with an abrupt transition between the chartaceous hairy body and the membranous glabrous tip, scaberulous on the margins, obtusely or acutely bilobed, with an awn 1–7 mm. long (rarely awnless but then the glume over 2.5 mm. long); lower floret barren, with or without a palea (its keels scaberulous), the lemma similar to the upper glume but 5-nerved and with an awn 3–12 mm. long.

Habitat

Upland grassland, Brachystegia wooded grassland and old cultivation; 1100–2100 m.

Distribution

K4/K6 T2 T3 T4 T6 T7 T8 Ethiopia, southward to Zimbabwe

Morphology General Habit

Perennial. Culms decumbent; 40-120 cm long; (0.6-)0.8-2.1 mm diam. Leaf-sheaths viscid; pilose; with tubercle-based hairs. Ligule a fringe of hairs; 0.5-1.2 mm long. Leaf-blades flat, or involute; 5-20 cm long; 2-10 mm wide; viscid. Leaf-blade surface glabrous, or pilose.

Morphology Reproductive morphology Inflorescences

Inflorescence a panicle. Panicle open; oblong; dense; 5-30 cm long; 1.5-6(-8) cm wide. Spikelets solitary. Fertile spikelets pedicelled. Pedicels bearing a few hairs; hairy above.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; compressed slightly; symmetrical; (2-)2.4-4.4(-5.2) mm long; with hairs extending 1-4 mm beyond apex; falling entire.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong; laterally compressed; compressed slightly; symmetrical; (2-)2.4-4.4(-5.2) mm long; with hairs extending 1-4 mm beyond apex; falling entire.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes dissimilar; reaching apex of florets; thinner than fertile lemma. Lower glume oblong; 0.5-1 mm long; 0.2 length of spikelet; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Lower glume apex obtuse. Upper glume oblong; not gibbous; chartaceous; much thinner above; without keels; 7 -veined. Upper glume lateral veins without ribs, or ribbed. Upper glume surface pubescent, or pilose. Upper glume hairs white, or purple. Upper glume apex lobed; 2 -fid; awned; 1 -awned. Upper glume awn 1-8 mm long.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret similar to upper glume; oblong; 1 length of spikelet; chartaceous; much thinner above; 5 -veined; distinctly veined, or without lateral veins; pubescent, or pilose; bearing white hairs, or purple hairs; lobed; 2 -fid; awned. Awn of lower sterile floret 1-12 mm long. Palea of lower sterile floret scabrous. Fertile lemma ovate; laterally compressed; 2-2.5 mm long; cartilaginous; without keel; 3-5 -veined. Lemma margins flat. Palea cartilaginous; without keels.

Morphology Reproductive morphology Flowers

Stigmas laterally exserted.

Distribution

Africa: west-central tropical, northeast tropical, east tropical, and southern tropical.

Reference

Paniceae. FTEA.