Polygonum L.

Scientific Description

Family Polygonaceae.

Habit and leaf form. Herbs. Annual; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves; arising from a taproot, fibrous root system or creeping rhizomes. Self supporting, or climbing; when climbing, stem twiners. Twining clockwise. Helophytic, or mesophytic, or xerophytic. Leaves alternate; spiral; ‘herbaceous’; petiolate to sessile; sheathing. Leaf sheaths not tubular; with free margins. Leaves gland-dotted, or not gland-dotted; simple; sometimes almost peltate, or not peltate; epulvinate. Leaf blades entire; pinnately veined; cross-venulate; cordate, or sagittate, or cuneate at the base, or rounded at the base. Leaves with stipules. Stipules intrapetiolar; concrescent; ochreate (ochreae deeply lacerate, silvery or white, glabrous); scaly. Leaf blade margins entire (or crisped), or crenate; flat, or revolute. Leaves without a persistent basal meristem. Leaf anatomy. Hairs absent (usually), or present. Stem anatomy. Nodes penta-lacunar to multilacunar. Secondary thickening absent, or developing from a conventional cambial ring, or anomalous.

Reproductive type, pollination. Fertile flowers hermaphrodite (usually). Unisexual flowers absent. Plants hermaphrodite (occasionally cleistogamous). Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers solitary, or aggregated in ‘inflorescences’; when solitary, axillary. Inflorescences axillary; lax and spike-like with axillary flowers in clusters or solitary; with involucral bracts, or without involucral bracts. Flowers small; regular; 4 merous, or 5 merous; cyclic to partially acyclic. If partially acyclic, the perianth acyclic and the androecium acyclic. Free hypanthium present, or absent. Hypogynous disk present (or nectaries present between the androecial members); annular. Perianth ambiguously with distinct calyx and corolla, or sepaline, or petaline, or of ‘tepals’ (depending on interpretation); 4, or 5; 1 -whorled; joined (and shallowly or deeply lobed, the lobes usually more or less equal); green, or white, or pink; fleshy, or non-fleshy; persistent; non-accrescent. Androecium 3–9. Androecial members branched, or unbranched; free of the perianth, or adnate; all equal, or markedly unequal; free of one another; 2 -whorled. Androecium exclusively of fertile stamens. Stamens 3–9. Filaments subulate above, broadly dilated in lower half. Anthers dorsifixed, or basifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse, or extrorse and introrse, or latrorse; tetrasporangiate. Gynoecium (2–)3 carpelled. The pistil 1 celled. Carpels isomerous with the perianth (when P cyclic). Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary unilocular; 1 locular. Locules secondarily divided by ‘false septa’ (or incompletely trilocular by false septa), or without ‘false septa’. The ‘odd’ carpel posterior. Gynoecium stylate (sometimes only shortly). Styles 2, or 3; free, or partially joined; apical. Stigmas 2, or 3; 1 - lobed; capitate; dry type; non-papillate; Group II type. Placentation basal. Ovules in the single cavity 1; funicled, or sessile; ascending; non-arillate; orthotropous to anatropous.

Fruit and seed features. Fruit non-fleshy; indehiscent; achene-like, or a nut (lenticular or trigonous, usually enclosed within the floral whorl, sometimes partly exserted); 1 seeded. Seeds endospermic. Endosperm ruminate, or not ruminate; oily. Perisperm present to absent (‘more or less absent’ ?). Seeds with starch. Cotyledons 2. Embryo curved. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Aluminium accumulation not found. Plants accumulating free oxalates. Photosynthetic pathway: C₃ and C₄.

Geography, cytology, number of species. Native of Australia. Not endemic to Australia. Australian states and territories: Western Australia, South Australia, Northern Territory, Queensland, New South Wales, Victoria, Australian Capital Territory, and Tasmania. South-West Botanical Province. N = 10, 11, 12, 14.