Antigonon Endl.

Scientific Description

Family Polygonaceae.

Habit and leaf form. Herbaceous climbers, or lianas. Herbs perennial; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Climbing; tendril climbers. Helophytic, or mesophytic, or xerophytic. Leaves alternate, or opposite; spiral; ‘herbaceous’; petiolate; 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. Leaves with stipules, or without stipules. Stipules intrapetiolar; concrescent; not ochreate (in A. leptopus, the petioles basally more or less amplexicaul), or ochreate; scaly. Leaf blade margins entire (or crisped), or crenate; flat, or revolute. Leaves without a persistent basal meristem. 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. Unisexual flowers absent. Plants hermaphrodite. Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in fascicles. Inflorescences terminal, or axillary; slightly branched, bearing lateral tendrils, especially on their distal portions and terminating in a forked tendril; with involucral bracts, or without involucral bracts. Flowers small to medium-sized; regular, or somewhat irregular (when perianth of 5 unequal members); 2 merous, or 3 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); 5, or 6 (then 3+3); 2 -whorled; isomerous, or anisomerous; free to joined; similar in the two whorls, or different in the two whorls; white, or pink; non-fleshy (papery); persistent; accrescent. Androecium (2–)6(–9). Androecial members branched, or unbranched; free of the perianth, or adnate (usually more or less perigynous ?); all equal, or markedly unequal; coherent (filaments basally connate); when cyclic, 2 -whorled (3+3, or spiralled). Androecium exclusively of fertile stamens. Stamens (2–)6(–9). 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–)3; free to partially joined; apical. Stigmas (2–)3; 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 (very acute and sharply trigonous in the upper half); 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. Adventive. Australian states and territories: Western Australia. N = 20.