Oxygonum stuhlmannii Dammer

Flora Zambesiaca. Vol. 9, Part 3. Polygonaceae-Myriaceae. Pope GV, Polhill RM, Martins ES. 2006.

Type

Type from Tanzania.

Morphology General Habit

Perennial herb, with several stems from a woody rootstock Perennial herb, with several stems from a woody rootstock.

Morphology Stem

Stems red-brown, trailing or ascending, 40–50 cm long, longitudinally striate, puberulous Stems red-brown, trailing or ascending, 40–50 cm long, longitudinally striate, puberulous.

Morphology Leaves

Leaves 1.5–5 × 0.6–1.2 cm, lanceolate or elliptic.lanceolate to ± deltate, apex acute, base narrowed into a petiole up to 1 cm long, margin usually ± shallowly lobed, sometimes entire, midrib prominent beneath, lamina sparsely puberulous on both surfaces Leaves 1.5–5 × 0.6–1.2 cm, lanceolate or elliptic-lanceolate to ± deltate, apex acute, base narrowed into a petiole up to 1 cm long, margin usually ± shallowly lobed, sometimes entire, midrib prominent beneath, lamina sparsely puberulous on both surfaces.

Morphology Leaves Ocrea

Ocrea 5–8 mm long, membranous, truncate with a terminal fringe of reddish wavy setae c. 5 mm long Ocrea 5–8 mm long, membranous, truncate with a terminal fringe of reddish wavy setae c. 5 mm long.

Morphology Reproductive morphology Flowers

Hermaphrodite flowers strongly heterostylous; perianth 5-lobed; tube 1.5 mm long, pubescent outside; lobes 2–2.5(5) mm long, oblong Male flowers not seen Flowers pedicellate, 1–4 in the axil of bracts, arranged in an elongated spiciform raceme up to c. 35 cm long; raceme erect or slightly arcuate; bracts 2.5–4 mm long, puberulous to glabrous, truncate, fringed at the apex with 3–5 setae c. 2 mm long; pedicels 4–6 mm long; bracteoles 2.5–4 mm long Flowers pedicellate, 1–4 in the axil of bracts, arranged in an elongated spiciform raceme up to c. 35 cm long; raceme erect or slightly arcuate; bracts 2.5–4 mm long, puberulous to glabrous, truncate, fringed at the apex with 3–5 setae c. 2 mm long; pedicels 4–6 mm long; bracteoles 2.5–4 mm long. Hermaphrodite flowers strongly heterostylous; perianth 5-lobed; tube 1.5 mm long, pubescent outside; lobes 2–2.5(5) mm long, oblong. Male flowers not seen.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 2–3 mm long; anthers 0.3–0.4 × 0.2–0.3 mm, ellipsoid

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary 3–3.5 mm long, fusiform; styles of long-styled flowers 3–3.5 mm long, free almost to the base, strongly exserted; styles of short-styled flowers c. 1 mm long

Ecology

On disturbed soils, sandy soils on roadsides, in miombo woodland; 775–2100 m.

Note

This species shows considerable variation in leaf shape and in the hairiness of the leaves. Oxygonum baumii, the type of which is the only record for Angola, was included here with doubt by Graham, loc. cit. (1957).

Distribution

MAL N Malawi Also in Dem. Rep. Congo (Kivu), Kenya, Tanzania and Angola.

sex Male

Male flowers not seen.

Morphology Reproductive morphology Flowers Androecium Stamens

Filaments 2–3 mm long; anthers 0.3–0.4 × 0.2–0.3 mm, ellipsoid.

sex Hermaphrodite

Filaments 2–3 mm long; anthers 0.3–0.4 × 0.2–0.3 mm, ellipsoid. Ovary 3–3.5 mm long, fusiform; styles of long-styled flowers 3–3.5 mm long, free almost to the base, strongly exserted; styles of short-styled flowers c. 1 mm long. Hermaphrodite flowers strongly heterostylous; perianth 5-lobed; tube 1.5 mm long, pubescent outside; lobes 2–2.5(5) mm long, oblong.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 3–3.5 mm long, fusiform; styles of long-styled flowers 3–3.5 mm long, free almost to the base, strongly exserted; styles of short-styled flowers c. 1 mm long.

Morphology Reproductive morphology Fruits

Nut c. 5 mm long, fusiform, trigonous, papillose, with 3 spreading prickles on the angles a little below the middle, 3–5 mm long. Nut c. 5 mm long, fusiform, trigonous, papillose, with 3 spreading prickles on the angles a little below the middle, 3–5 mm long.