Oxygonum buchananii (Dammer) J.B.Gillett

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

Type

Lectotype, selected by Graham (1957): Malawi, Buchanan 550 (K, lectotype).

Morphology General Habit

A robust perennial herb, sometimes bushy, with a rootstock A robust perennial herb, sometimes bushy, with a rootstock.

Morphology Stem

Stems several from the rootstock, up to 1 m long, prostrate or spreading, longitudinally striate, glabrous or sparsely papillate Stems several from the rootstock, up to 1 m long, prostrate or spreading, longitudinally striate, glabrous or sparsely papillate.

Morphology Leaves

Leaves petiolate, dark green above, paler beneath; lamina 7.5–10 × 4.5–6 cm, obovate to broadly ovate, obtuse or shortly acuminate at the apex, attenuate at the base and decurrent on the petiole, with the midrib prominent beneath, entire or slightly wavy on the margin, glabrous on both surfaces, gland-dotted beneath; petiole 1–2 cm long Leaves petiolate, dark green above, paler beneath; lamina 7.5–10 × 4.5–6 cm, obovate to broadly ovate, obtuse or shortly acuminate at the apex, attenuate at the base and decurrent on the petiole, with the midrib prominent beneath, entire or slightly wavy on the margin, glabrous on both surfaces, gland-dotted beneath; petiole 1–2 cm long.

Morphology Leaves Ocrea

Ocrea brown, 0.5–2 cm long, glabrous outside, truncate with a terminal fringe of 7–9 setae 1–3 cm long Ocrea brown, 0.5–2 cm long, glabrous outside, truncate with a terminal fringe of 7–9 setae 1–3 cm long.

Morphology Reproductive morphology Flowers

Male flowers not seen Flowers pedicellate, 2–4 in the axils of bracts, arranged in elongated spiciform terminal racemes up to 36 cm long; bracts 4–5 mm long, truncate but produced dorsally into an acute setose apex, with or without a terminal fringe of short setae up to 1 mm long; pedicels red-brown, 6–7 mm long, glabrous Hermaphrodite flowers heterostylous, long-styled flowers not seen; perianth yellowish-green, glabrous, 5-lobed; tube 2–3 mm long; lobes 3–4 mm long, oblong Flowers pedicellate, 2–4 in the axils of bracts, arranged in elongated spiciform terminal racemes up to 36 cm long; bracts 4–5 mm long, truncate but produced dorsally into an acute setose apex, with or without a terminal fringe of short setae up to 1 mm long; pedicels red-brown, 6–7 mm long, glabrous. Male flowers not seen. Hermaphrodite flowers heterostylous, long-styled flowers not seen; perianth yellowish-green, glabrous, 5-lobed; tube 2–3 mm long; lobes 3–4 mm long, oblong.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 0.3–3.5 mm long, filiform and flattened toward the base; anthers orange, 0.5–0.55 × 0.4–0.45 mm, oblong

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary 3.4 × 2.3 mm, oblong; styles c. 1 mm long

Ecology

Clay sandy soils in dry river margins; 250–700 m.

Distribution

Malawi ZAM E, MAL S, MOZ N Zambia Mozambique Also in southern Tanzania and Angola.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 3.4 × 2.3 mm, oblong; styles c. 1 mm long.

sex Hermaphrodite

Ovary 3.4 × 2.3 mm, oblong; styles c. 1 mm long. Filaments 0.3–3.5 mm long, filiform and flattened toward the base; anthers orange, 0.5–0.55 × 0.4–0.45 mm, oblong. Hermaphrodite flowers heterostylous, long-styled flowers not seen; perianth yellowish-green, glabrous, 5-lobed; tube 2–3 mm long; lobes 3–4 mm long, oblong.

Morphology Reproductive morphology Fruits

Nut 8–10 mm across, trigonous, with a spine on each angle; spines 2–3 mm long, pointing somewhat downwards. Nut 8–10 mm across, trigonous, with a spine on each angle; spines 2–3 mm long, pointing somewhat downwards.

sex Male

Male flowers not seen.

Morphology Reproductive morphology Flowers Androecium Stamens

Filaments 0.3–3.5 mm long, filiform and flattened toward the base; anthers orange, 0.5–0.55 × 0.4–0.45 mm, oblong.