Oxygonum pachybasis Milne-Redh.

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

Type

Type:Zambia, Solwezi, 20.ix.1930, Milne-Redhead 1162 (K, holotype).

Habit

An erect or ± decumbent perennial herb with many stems from a thick woody rootstock An erect or ± decumbent perennial herb with many stems from a thick woody rootstock.

Stem

Stems annual, reddish-brown, 8–35 cm long, longitudinally striate, leafless at the base, ± pubescent Stems annual, reddish-brown, 8–35 cm long, longitudinally striate, leafless at the base, ± pubescent.

Flowers

Hermaphrodite flowers heterostylous; perianth white with lobes tinged pink outside; tube 1.5–2 mm long, puberulous outside; lobes 4–7 × 3 mm long, ovate-elliptic to oblong-elliptic. Filaments 2–5 mm long; anthers 0.9–1 × 0.35–0.4 mm Flowers pedicellate, 2–6 in the axils of bracts, arranged in terminal and lateral spiciform racemes up to 17 cm long, pedicels 5–8 mm long, accrescent up to 12 mm and reflexed in fruit; bracts chartaceous, obliquely truncate and produced dorsally into an acute subulate seta, sometimes with a fringe of short setae. Male flowers not seen Flowers pedicellate, 2–6 in the axils of bracts, arranged in terminal and lateral spiciform racemes up to 17 cm long, pedicels 5–8 mm long, accrescent up to 12 mm and reflexed in fruit; bracts chartaceous, obliquely truncate and produced dorsally into an acute subulate seta, sometimes with a fringe of short setae Hermaphrodite flowers heterostylous; perianth white with lobes tinged pink outside; tube 1.5–2 mm long, puberulous outside; lobes 4–7 × 3 mm long, ovate-elliptic to oblong-elliptic. Male flowers not seen.

Ovary

Ovary 0.5–1 mm long; style connate in the lower c. 2 mm, 3-branched; style of long-styled flowers 4–6.5 mm long; style of short-styled flowers (1)1.5–2.5(3) mm

Fruits

Nut reddish-brown when mature, 7–9 × 4–5 mm, ovoid-trigonous, longitudinally striate, unwrinkled or very irregularly wrinkled, puberulous. Nut reddish-brown when mature, 7–9 × 4–5 mm, ovoid-trigonous, longitudinally striate, unwrinkled or very irregularly wrinkled, puberulous.

Ecology

Miombo and Cryptosepalum woodland, roadsides, recently burnt ground; 1350–1600 m.

Note

Following the study of material from the Flora Zambesiaca area and other countries, we conclude that O. vanderystii Robyns is conspecific with O. pachybasis. Putative differences related to stem length and consistency (Robyns 1944, 1948) and morphology of fruits (Graham 1957) are, in our opinion, questionable: stem length and texture are highly variable and fruits are always trigonous, including those of the type of O. pachybasis.

Distribution

ZAM N, ZAM W Also in SW Tanzania, Dem. Rep. Congo and Angola. Zambia

Leaves

Leaves 3.5–6 × 0.9–1.3 cm, elliptic-lanceolate to lanceolate, acute apiculate at the apex, attenuate at the base, entire on the margins, pubescent to glabrescent, midrib prominent beneath. Leaves 3.5–6 × 0.9–1.3 cm, elliptic.lanceolate to lanceolate, acute apiculate at the apex, attenuate at the base, entire on the margins, pubescent to glabrescent, midrib prominent beneath

Ocrea

Ocrea reddish-brown, 0.8–1.3 cm long, truncate with a fringe of brownish setae 3–7 mm long at the apex, ± pubescent. Ocrea reddish-brown, 0.8–1.3 cm long, truncate with a fringe of brownish setae 3–7 mm long at the apex, ± pubescent

Male

Male flowers not seen.

Stamens

Filaments 2–5 mm long; anthers 0.9–1 × 0.35–0.4 mm.

Hermaphrodite

Filaments 2–5 mm long; anthers 0.9–1 × 0.35–0.4 mm. Ovary 0.5–1 mm long; style connate in the lower c. 2 mm, 3-branched; style of long-styled flowers 4–6.5 mm long; style of short-styled flowers (1)1.5–2.5(3) mm. Hermaphrodite flowers heterostylous; perianth white with lobes tinged pink outside; tube 1.5–2 mm long, puberulous outside; lobes 4–7 × 3 mm long, ovate-elliptic to oblong-elliptic.

Pistil

Ovary 0.5–1 mm long; style connate in the lower c. 2 mm, 3-branched; style of long-styled flowers 4–6.5 mm long; style of short-styled flowers (1)1.5–2.5(3) mm.