Persicaria (L.) Mill.

Scientific Description

Family Polygonaceae.

Habit and leaf form. Herbs (with erect to decumbent stems, often rooting at the nodes, rarely with a slender rhizome), or herbaceous climbers. Annual, or perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Self supporting, or climbing; when climbing, stem twiners. Hydrophytic, or helophytic to mesophytic. Leaves submerged, or emergent, or floating; alternate (more or less evenly distributed along stems); spiral; ‘herbaceous’; petiolate, or subsessile; 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; auriculate at the base, or cordate, or hastate, or sagittate, or attenuate at the base, or cuneate at the base, or rounded at the base. Leaves with stipules. Stipules intrapetiolar; concrescent; ochreate (ochreae entire, truncate, sometimes ciliate on upper margin); scaly. Leaf blade margins entire (or crisped), or crenate; flat, or revolute (rarely). Leaves without a persistent basal meristem. Leaf anatomy. Hairs present, or absent. Stem anatomy. Nodes penta-lacunar to multilacunar. Secondary thickening absent, or developing from a conventional cambial ring, or anomalous; when anomalous, via concentric cambia.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite (occasionally cleistogamous). Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in fascicles. Inflorescences terminal (usually); paniculate, spike-like or capitate; with involucral bracts, or without involucral bracts; often conspicuously ochreolate. Flowers pedicellate. Pedicels articulate, short. Flowers small; regular; 2 merous, or 3 merous, or 5 merous; cyclic to partially acyclic. When 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); (3–)5; 1 -whorled, or 2 -whorled; joined (deeply lobed); when biseriate, similar in the two whorls, or different in the two whorls; green, or white, or pink; fleshy, or non-fleshy; persistent; non-accrescent (not markedly enlarged or winged). Androecium 5–8. Androecial members branched, or unbranched; free of the perianth, or adnate (usually more or less perigynous ?); all equal, or markedly unequal; free of one another, or coherent (filaments basally connate ?); when cyclic, 2 -whorled. Androecium exclusively of fertile stamens. Stamens 5–8. Anthers dorsifixed, or basifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse, or extrorse and introrse, or latrorse; tetrasporangiate. Gynoecium 2 carpelled, or 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(–3); partially joined; simple (filiform); apical. Stigmas 2(–3); 1 - lobed; capitate; dry type; papillate, or 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 to subglobular, enclosed in floral segments or 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 straight to 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, and New South Wales. Northern Botanical Province and Eremaean Botanical Province. N = 10, 11, 12.