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This genus is accepted, and its native range is Tropical & S. Africa, Madagascar, Arabian Peninsula.
Oxygonum alatum Burch.

[FZ]

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

Morphology General Habit
Annual or perennial polygamous herbs, more rarely shrubs, glabrous or hairy, sometimes with papillae or scales A shrub or scrambling plant from a woody rootstock, ± pubescent Annual or perennial polygamous herbs, more rarely shrubs, glabrous or hairy, sometimes with papillae or scales.
Morphology Leaves
Leaves alternate, sessile or petiolate, entire or pinnatifid Leaves alternate, sessile or petiolate, entire or pinnatifid. Leaves sessile, dull green, 2–6.8 × 0.3–1.3(1.7) cm, elliptic.lanceolate, acute at the apex often mucronate, attenuate to the base, entire or slightly sinuous on the margin, with the midrib prominent beneath, ± pubescent and punctate with black dots on both surfaces
Morphology Leaves Ocrea
Ocrea membranous or chartaceous, with or without a fringe of setae at the apex Ocrea membranous or chartaceous, with or without a fringe of setae at the apex. Ocrea 10–15 mm long, chartaceous, thinly covered with short hairs, truncate and fringed with red-brown setae c. 8 mm long at the apex
Morphology Stem
Stems sometimes much branched; branches ascending; bark red-brown
Morphology Reproductive morphology Flowers
Hermaphrodite flowers heterostylous; perianth wine-red outside and white inside, tubular with 5 spreading lobes; tube 6–8 mm long and slightly constricted at the apex; lobes 5–8 mm long, oblong-lanceolate or oblong-oblanceolate, acute or apiculate at the apex Flowers pedicellate, clustered in axils of bracts, borne in slender or laxly spiciform, terminal or axillary, leafless racemes; bracteoles 2, united; pedicels becoming thicker and sometimes longer as the fruit matures Hermaphrodite flowers heterostylous, 4–5-merous; perianth tubular, with relatively short lobes; as the fruit matures the receptacle enlarges and invests the fruit with the withered perianth persisting above it and constricted at the base; stamens 8 in 2 series, the 5 outer stamens adnate to the perianth segments near their bases, the 3 inner with flattened bases forming a contiguous ring around the base of the style; anthers oblong; styles 3; stigmas capitate Hermaphrodite flowers heterostylous, 4–5-merous; perianth tubular, with relatively short lobes; as the fruit matures the receptacle enlarges and invests the fruit with the withered perianth persisting above it and constricted at the base; stamens 8 in 2 series, the 5 outer stamens adnate to the perianth segments near their bases, the 3 inner with flattened bases forming a contiguous ring around the base of the style; anthers oblong; styles 3; stigmas capitate. Male flowers with a short tube and 4–5 petaloid perianth segments Flowers pedicellate, clustered in axils of bracts, borne in slender or laxly spiciform, terminal or axillary, leafless racemes; bracteoles 2, united; pedicels becoming thicker and sometimes longer as the fruit matures. Male flowers with a short tube and 4–5 petaloid perianth segments. Male flowers not seen Flowers pedicellate, 1–3 in the axils of bracts, arranged in terminal spiciform rigid racemes c. 25 cm long; bracts 7–10 mm long, chartaceous, obliquely truncate and produced dorsally into an acute or acuminate setose apex, glabrous or ± puberulous; bracteoles 2, c. 5 mm long, hyaline with 1–2 short setae at the apex; pedicels c. 6 mm long, articulated near the apex
Morphology Reproductive morphology Flowers Androecium Stamens Filaments
Filaments (1.5)4–11 mm long, filiform; anthers 1–1.3 × 0 4–0.5 mm
Morphology Reproductive morphology Flowers Gynoecium Ovary
Ovary 7–8 mm long, ellipsoid, glabrous; styles of long-styled flowers 6–7 mm long; styles of short-styled flowers 4–5 mm shorter than the stamens
Morphology Reproductive morphology Fruits
Nut red-brown at maturity, 9–12 × 4–5 mm, oblong-ellipsoid, glabrous, longitudinally sulcate and transversally wrinkled. Fruiting receptacle hardened and enclosing the fruit Fruiting receptacle hardened and enclosing the fruit. Nut fusiform, conical, ampulliform or lanceolate-ampulliform, trigonous or not, unarmed or with 3(9) spreading prickles or teeth of varying size and development at the centre or below, or at the base, sometimes winged. Nut fusiform, conical, ampulliform or lanceolate-ampulliform, trigonous or not, unarmed or with 3(9) spreading prickles or teeth of varying size and development at the centre or below, or at the base, sometimes winged.
Ecology
Miombo and Cryptosepalum woodland, often on Kalahari Sands; 1000–1750 m.
Distribution
A genus of c. 35 species, mostly confined to Africa where it is widespread, one species being endemic in Madagascar. ZAM B, ZAM N, ZAM W Zambia Also in Angola and Dem. Rep. Congo.

[FTEA]

Polygonaceae, R. A. Graham. Flora of Tropical East Africa. 1958

Morphology General Habit
Polygamous, heterostylous, annual or perennial herbs or more rarely shrubs
Morphology Leaves Ocrea
Ocreae with or without a terminal fringe of setae
Morphology Reproductive morphology Flowers
Flowers borne in axillary, leafless, often triquetrous, rather slender and elongated spiciform racemes Hermaphrodite flowers tubular, the tepals marcescent, the tube very accrescent around the ovary Male flowers with a very short tube and 4–5 petaloid tepals
Morphology Reproductive morphology Inflorescences Bracteoles
Bracteoles 2, conjoined
sex Male
Male flowers with a very short tube and 4–5 petaloid tepals
sex Hermaphrodite
Hermaphrodite flowers tubular, the tepals marcescent, the tube very accrescent around the ovary
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 8, in 2 series; 5 outer adnate to the tepals near their bases, 3 inner with flattened bases forming a contiguous ring around the base of the style
Morphology Reproductive morphology Flowers Gynoecium Pistil
Styles 3, free or conjoined below; stigmas capitate
Morphology Reproductive morphology Fruits
Fruiting perianth fusiform, conical, ampulliform or lanceolate-ampulliform, trigonous or not, unarmed, or with 3 (–9) spreading prickles of varying size and development at the centre or below, or at the base, rarely with 3 additional prickles or teeth on the angles of the lower half, sometimes winged.

[FSOM]

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Herbs or shrubs, glabrous or hairy
Morphology Leaves Stipules
Ochreae with or without bristles at the margin
Morphology Reproductive morphology Inflorescences
Flowers bisexual or male, borne in axillary leafless, rather slender and elongated spikes
Morphology Reproductive morphology Flowers
Male flowers with a very short tube and 4–5 petaloid tepals Hermaphrodite flowers heterostylous, tubular, the tube enlarging around the ovary, with 4–5 lobes
Morphology Reproductive morphology Flowers Androecium Stamens
Stamens 8, the 5 outer adnate to the perianth near the base, the 3 inner with flattened bases forming a ring around the style
Morphology Reproductive morphology Flowers Gynoecium Style
Styles 3; stigmas capitate
Morphology Reproductive morphology Fruits
Fruit sometimes trigonous, often armed with prickles, or sometimes winged.
Distribution
Genus of some 37 species, mainly native to Africa, including Madagascar (also to Arabia) and introduced in India.

Native to:

Angola, Botswana, Burundi, Cape Provinces, Caprivi Strip, Chad, Djibouti, Eritrea, Ethiopia, Free State, Kenya, KwaZulu-Natal, Madagascar, Malawi, Mozambique, Namibia, Niger, Northern Provinces, Rwanda, Saudi Arabia, Socotra, Somalia, Sudan, Swaziland, Tanzania, Uganda, Yemen, Zambia, Zaïre, Zimbabwe

Introduced into:

Cape Verde, India, Mauritius

Oxygonum Burch. ex Campd. appears in other Kew resources:

First published in Monogr. Rumex: 18 (1819)

Accepted by

  • Schuster, T.M., Reveal, J.L., Bayly, M.J. & Kron, K.A. (2015). An updated molecular phylogeny of Polygonoideae (Polygonaceae): relationships of Oxygonum, Pteroxygonum, and Rumex, and a new circumscription of Koenigia Taxon 64: 1188-1208.

Literature

Flora Zambesiaca

  • Bothalia 18: 173–181 (1988).
  • Bull. Jard. Bot. État 17: 157–164 (1944).
  • F.T.E.A., Polygonaceae: 26–38 (1958).
  • Germishuizen in Bothalia 18: 173–181 (1988).
  • Graham in Kew Bull. 12: 145–172 (1957)
  • Kew Bull. 12: 145–172 (1957)
  • Meisner in de Candolle, Prodr. 14: 38–39 (1856).
  • Monogr. Rumex: 14, 18 & 19 (1819).
  • Robyns in Bull. Jard. Bot. État 17: 157–164 (1944).
  • de Candolle, Prodr. 14: 38–39 (1856).
  • in F.T.E.A., Polygonaceae: 26–38 (1958).

Flora of Somalia

  • Flora Somalia, Vol 1, (1993) Author: by M. Thulin [updated by M. Thulin 2008]
  • Graham in Kew Bull. 11: 145 (1957).

Flora of Tropical East Africa

  • R. Grah. in K.B. 1957: 145 (1957)
  • Trav. 1: 548 (1822)

Flora Zambesiaca
Flora Zambesiaca
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Somalia
Flora of Somalia
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0