Oxygonum sinuatum (Hochst. & Steud. ex Meisn.) Dammer

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

Type

Type from Ethiopia.

Morphology Reproductive morphology Flowers Gynoecium Style

Styles 2 mm long, connate at the base for c. 0.5 mm; stigmas of long-styled flowers reaching only to the tip of the anthers or to slightly beyond, stigmas of short-styled flowers reaching or nearly reaching the anther bases

Ecology

Sandy roadsides, disturbed soils, sandy soils on stream banks and woodlands; 450–1600 m.

Note

This species may be confused with O. stuhlmannii and O. atriplicifolium. O sinuatum is an annual while O. stuhlmannii is a perennial herb; in O. atriplicifolium the flowers are strongly heterostylous and the pedicels are filiform and reflexed in fruit while in O. sinuatum the pedicels are stout, c. 5 mm long and ± erect or spreading in fruit.

Distribution

Mozambique Malawi Zimbabwe Botswana Caprivi Strip Zambia BOT N, BOT SE, ZAM B, ZAM N, ZAM W, ZAM C, ZAM E, ZAM S, ZIM N, ZIM W, ZIM C, ZIM E, ZIM S, MAL N, MAL C, MAL S, MOZ N, MOZ T, MOZ GI, MOZ M Widespread in tropical eastern Africa from Sudan and Ethiopia southwards to Namibia and South Africa, also in Dem. Rep. Congo and Angola. Sandy roadsides, disturbed soils, sandy soils on stream banks and woodlands; 450–1600 m.

Morphology General Habit

A diffuse, erect or decumbent annual herb. A diffuse, erect or decumbent annual herb

Morphology Stem

Stems green to reddish-brown, up to c. 1 m tall, branched, longitudinally striate, glabrous or pubescent. Stems green to reddish-brown, up to c. 1 m tall, branched, longitudinally striate, glabrous or pubescent

Morphology Leaves

Leaves petiolate, lamina 4–8 × 1–3 cm, ovate to ovate-elliptic or ovate-lanceolate to elliptic-lanceolate in outline, usually deeply incised with 1–3 rounded or acute lobes on each side, often panduriform or lyrate, narrowed to each end, midrib prominent beneath; petioles 1–2 cm long. Leaves petiolate, lamina 4–8 × 1–3 cm, ovate to ovate-elliptic or ovate-lanceolate to elliptic.lanceolate in outline, usually deeply incised with 1–3 rounded or acute lobes on each side, often panduriform or lyrate, narrowed to each end, midrib prominent beneath; petioles 1–2 cm long

Morphology Leaves Ocrea

Ocrea reddish, up to c. 5.5 mm long, truncate and fringed with setae at the apex. Ocrea reddish, up to c. 5.5 mm long, truncate and fringed with setae at the apex

Morphology Reproductive morphology Flowers

Flowers pedicellate, 2–5 in the axil of each bract, arranged in spiciform terminal or axillary racemes up to 28–45 cm long, sometimes longer; bracts up to c. 6 mm apart, obliquely truncate, acute or acuminate with a fringe of setae at the apex; pedicels of hermaphrodite flowers stout and 4–5 mm long, pedicels of male flowers filiform and withering. Flowers pedicellate, 2–5 in the axil of each bract, arranged in spiciform terminal or axillary racemes up to 28–45 cm long, sometimes longer; bracts up to c. 6 mm apart, obliquely truncate, acute or acuminate with a fringe of setae at the apex; pedicels of hermaphrodite flowers stout and 4–5 mm long, pedicels of male flowers filiform and withering Hermaphrodite flowers slightly heterostylous; perianth white or pink, 4–5-lobed; tube 1–1.5 mm long; lobes 2.5–3(4) mm long and ovate-elliptic. Filaments 2 mm long in long-styled flowers, 1.5 mm long in short-styled flowers Male flowers not seen Hermaphrodite flowers slightly heterostylous; perianth white or pink, 4–5-lobed; tube 1–1.5 mm long; lobes 2.5–3(4) mm long and ovate-elliptic. Male flowers not seen.

sex Male

Male flowers not seen.

sex Hermaphrodite

Hermaphrodite flowers slightly heterostylous; perianth white or pink, 4–5-lobed; tube 1–1.5 mm long; lobes 2.5–3(4) mm long and ovate-elliptic. Styles 2 mm long, connate at the base for c. 0.5 mm; stigmas of long-styled flowers reaching only to the tip of the anthers or to slightly beyond, stigmas of short-styled flowers reaching or nearly reaching the anther bases. Filaments 2 mm long in long-styled flowers, 1.5 mm long in short-styled flowers.

Morphology Reproductive morphology Flowers Androecium Stamens Filaments

Filaments 2 mm long in long-styled flowers, 1.5 mm long in short-styled flowers.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Styles 2 mm long, connate at the base for c. 0.5 mm; stigmas of long-styled flowers reaching only to the tip of the anthers or to slightly beyond, stigmas of short-styled flowers reaching or nearly reaching the anther bases.

Morphology Reproductive morphology Fruits

Nut 5–7 mm long, fusiform, trigonous, pubescent or papillose, rarely glabrous, usually erect or spreading, seldom pendulous, with 3 spreading prickles 1.5–2 mm long on the angles, centrally or sometimes just below the middle, rarely with 3 smaller prickles on the faces between the angles. Nut 5–7 mm long, fusiform, trigonous, pubescent or papillose, rarely glabrous, usually erect or spreading, seldom pendulous, with 3 spreading prickles 1.5–2 mm long on the angles, centrally or sometimes just below the middle, rarely with 3 smaller prickles on the faces between the angles.