Emex Campd.

Scientific Description

Family Polygonaceae.

Habit and leaf form. Robust herbs. Annual; plants with a basal concentration of leaves, or with neither basal nor terminal concentrations of leaves. Helophytic, or mesophytic, or xerophytic. Leaves alternate; 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 (or truncate). Leaves with stipules. Stipules intrapetiolar; concrescent; ochreate (ochreae translucent, soon lacerated or deciduous); 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 functionally male and functionally female. Unisexual flowers present. Plants monoecious. The unisexual flowers aggregated in different parts of the same inflorescence (the pistillate flowers at the base of inflorescence). Anemophilous, or entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in fascicles. Inflorescences axillary; appearing racemose by loss of upper leaves; with involucral bracts, or without involucral bracts. Flowers pedicellate (male flowers), or subsessile to sessile (in female 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. 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); 5–6 (in male flowers), or 6 (in female flowers); 2 -whorled; joined (the perianth segments spreading in male flowers; in female flowers the tube ovoid, 3 or 6 angled in fruit, more or less transversely ribbed between angles; outer series of lobes spiny in fruit, inner obtuse or aristate); similar in the two whorls, or different in the two whorls; fleshy, or non-fleshy; persistent; accrescent (and hardened in fruit). Fertile stamens present, or absent (female flowers). Androecium 4–6. 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 (3+3, or spiralled). Androecium exclusively of fertile stamens. Stamens 4–6. Anthers dorsifixed, or basifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse, or extrorse and introrse, or latrorse; tetrasporangiate. Fertile gynoecium present, or absent (male flowers). 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 3; free to partially joined; apical. Stigmas 3; dilated; 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 (trigonous, enclosed within persistent hypanthium); 1 seeded. Seeds subterete; 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, South Australia, Northern Territory, Queensland, New South Wales, Victoria, and Australian Capital Territory. South-West Botanical Province. N = 10.