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This is a large family, mostly from the temperate parts of the Northern Hemisphere but with some species in southern temperate areas and a few in the tropics. In Australia, most species are associated with seasonally wet or marshy areas, from the coasts to the arid interior; they only rarely occur in closed forests or shady sites. Some species are serious weeds of pastures and gardens.

Characteristic features of the family Polygonaceae in Australia include:

  • herbs or shrubs, occasionally twining, with rosetted or cauline leaves which are often hastate or sagittate (arrow-head shaped) at the base, or sometimes the leaves much reduced
  • stipules present and characteristically forming a dry, membranous sheath (ochrea) around the stem at the base of the petiole
  • flowers small, greenish, white or pink, regular, bisexual, with perianth parts in one whorl (or if in 2 whorls then the parts all similar)
  • ovary superior with one ovule, developing into a usually angular, grain-like nutlet


Evergreen or semi-deciduous shrubs, or woody or herbaceous vines climbing by twining stems, or annual, biennial or perennial terrestrial herbs, or aquatic herbs rooted in the substrate with their leaves emergent. Perennation by taproots or crowns. Vegetative reproduction absent or by rhizomes or root suckers. Leaves sometimes ±absent. Stems unarmed, or rarely with thorns or spines arising from the leaf axils; nodes conspicuously swollen or not; internodes solid, spongy, pithy or hollow, terete or angular. Extra-floral nectaries absent or on the foliage. Internal secretions not obvious. Plants glabrous, or with simple, stellate, clavate, capitate or vesicular glandular or non-glandular, unicellular, uniseriate or multiseriate hairs. Leaves alternate and spiral, or distichous, or rarely entirely absent, cauline or both basal and cauline if herbs, petiolate or subsessile. Stipules absent or present and ochreate, scale-like, or membranous, or lacerate, or fimbriate, falling off early or persistent. Lamina simple, symmetric, pinnatifid or pinnatisect, filiform, acicular, subulate, linear, lanceolate, ovate, elliptic, oblanceolate, oblong or orbicular; base cuneate, attenuate, rounded, cordate, hastate, sagittate or oblique; margins entire, rarely crenate, dentate, serrate or sinuate, ±flat, revolute or recurved; venation pinnate, or rarely 1-veined, parallel or veinless, with the midrib usually conspicuous, and the tertiary venation reticulate or not; surfaces punctate or not punctate; herbaceous or leathery; distinctive odour absent or aromatic. All the flowers bisexual, or with bisexual flowers occurring together with male flowers on some plants and bisexual flowers and female flowers occurring on other plants, or male and female flowers occurring on separate plants, or rarely occurring on the same plant. Inflorescences terminal or axillary, consisting of solitary flowers, or apparently of racemes, panicles, clusters, or dichasial or monochasial cymes. Bracts present or absent. Bracteoles present or apparently absent. Pollination by wind. Flowers odourless or fragrant, stalked. Floral disc present or absent; nectaries absent or present on the disc or the stamens. Perianth regular, of 2 dissimilar or similar whorls or of 1 whorl only, imbricate in bud. Calyx segments free or fused, with apparently 3 or 5 sepals or lobes; calyx cup-shaped or bell-shaped, herbaceous or papery. Corolla segments free or fused, with apparently 3 petals or lobes, alternating with the calyx segments, white, cream, yellow, pink, green, grey, brown or black, without contrasting markings, herbaceous, membranous or papery; claws absent; lobes ±entire; base spurs. Fertile stamens 4–9, opposite to or not clearly correlated with the sepals or calyx lobes, free of the corolla, free of the ovary and style, distinct from each other, all ±equal. Anthers dorsifixed or basifixed, versatile or not versatile, opening inwards by longitudinal slits, 2 or 4-celled. Ovary superior and sessile. Carpels 2–4, fused; ovary with 1 locule. Style terminal, single and branched above, branching from the base, or absent and the stigma ±sessile. Ovule 1, stalked; placentation basal or free-central. Fruit a dry, indehiscent achene or a nut; the perianth on the maturing fruit dry and persistent or growing larger. Disseminule macro-surface featureless or winged; micro-surface ±smooth, tuberculate or rugose, white, cream, green, brown or black, rarely grey, glossy or dull. Seeds 1 per fruit. Aril absent. Cotyledons 2. Embryo straight or curved.
(Note: this description has been generated from the coded data compiled for the key. Any errors in the key data will be reflected in the descriptions.)

A treatment of the family Polygonaceae has not yet been published in the Flora of Australia. It will appear in Volume 5.

Australian genera of Polygonaceae (as recognised for the Flora of Australia)

† = some species native, others introduced
* = all species introduced


Acetosa vesicaria (fruits)
Photo: B.Fuhrer © B.Fuhrer 

Muehlenbeckia adpressa (flowers)
Photo: D.Greig © ANBG 

Muehlenbeckia florulenta (flowers)
Photo: M.Fagg © ANBG 

Muehlenbeckia florulenta (habit)
Photo: A.Lyne © ANBG