Common name. Staggerweeds. Family Lamiaceae.
Habit and leaf form. Herbs; evergreen; bearing essential oils. Plants unarmed. Annual, or perennial. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Young stems tetragonal. To 0.03–0.35 m high. Leaves small to medium-sized; not fasciculate; opposite; not decurrent on the stems; petiolate; foetid; simple; epulvinate. Leaf blades entire; flat; broad ovate, or ovate, or triangular (broad); pinnately veined, or pinnately veined to palmately veined; cross-venulate; truncate to sub- cordate, or cuneate at the base (rarely). Mature leaf blades adaxially scattered, long, multicellular hairs pilose; abaxially pilose. Leaves without stipules. Leaf blade margins regularly toothed to crenate, or entire; flat. Leaves without a persistent basal meristem. Leaf anatomy. Hairs present; glandular hairs present; complex hairs absent. Branched hairs present. Urticating hairs absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous, or ornithophilous; usually via hymenoptera, or via lepidoptera, or via diptera.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescence few-flowered. Flowers in verticils. The terminal inflorescence unit cymose. Inflorescences terminal; a terminal leafy spike with flowers in few-flowered verticillasters. Flowers sessile, or subsessile; bracteate; small; very irregular; zygomorphic; cyclic; tetracyclic. Floral receptacle developing a gynophore, or with neither androphore nor gynophore. Free hypanthium absent. Perianth with distinct calyx and corolla; 4–10; 2 -whorled; isomerous, or anisomerous. Calyx present; 5; 1 -whorled; gamosepalous; blunt-lobed, or toothed; imbricate, or open in bud; exceeded by the corolla; campanulate, or tubular; unequal but not bilabiate (5 narrow, almost equal lobes, lower lobes narrower than upper lobes); lobes often purple; non-fleshy; persistent; with the median member posterior. Calyx lobes narrowly triangular. Corolla present; disguisedly 5; 1 -whorled; gamopetalous; blunt-lobed; imbricate; bilabiate (with an erect, hooded upper lip and a spreading 3-lobed lower lip); hairy adaxially (usually with a ring of hairs inside); plain, or with contrasting markings; pink to purple, or white, or pink (pale). Corolla lobes broadly oblong, or obovate (narrow; upper lip). Corolla members entire. Androecium present. Fertile stamens present. Androecial members definite in number. Androecium 4. Androecial members adnate; markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens 4. Staminal insertion midway down the corolla tube, or in the throat of the corolla tube. Stamens remaining included; didynamous; all more or less similar in shape; reduced in number relative to the adjacent perianth; fertile stamens representing the posterior-lateral pair and the anterior-lateral pair; oppositisepalous; all alternating with the corolla members. Anthers connivent, or separate from one another; dorsifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse; bilocular (loculi strongly divergent); tetrasporangiate; unappendaged. Pollen shed as single grains. Fertile gynoecium present. Gynoecium 2 carpelled (the carpels deeply lobed to mimic G4). The pistil 4 celled. Carpels reduced in number relative to the perianth. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular (originally), or 4 locular (by intrusions of the ovary wall constituting ‘ false septa’). Locules secondarily divided by ‘false septa’. Gynoecium median; stylate. Styles 1; simple; from a depression at the top of the ovary (the ovary deeply lobed); ‘gynobasic’; much longer than the ovary at anthesis; not becoming exserted. Stigmas 2, or 1 (by reduction); 2 - lobed. Placentation basal. Ovules 2 per locule, or 1 per locule (two per original loculus, but one per locellus); ascending; apotropous; non-arillate; anatropous, or hemianatropous.
Fruit and seed features. Fruit non-fleshy, or fleshy; a schizocarp. Mericarps (2–)4; comprising nutlets. Seeds endospermic to non-endospermic; small. Embryo well differentiated. Cotyledons 2. Embryo straight.
Special features. The flowering nodes separated by extended internodes. 1–3 flowers subtended by each floral leaf, or 4–25 flowers subtended by each floral leaf. Calyx limb 5 lobed. Corolla tube exceeding the calyx, or not exceeding the calyx. The upper lip of the corolla incorporating 2 members, the lower 3; (posterior, adaxial) lip of the corolla entire; upper (adaxial) lip of the corolla markedly concave. Lower (abaxial) lip of the corolla 3 lobed; not concave. Stamens ascending. The anterior pair of stamens exceeding the posterior pair.
Geography, cytology, number of species. Adventive. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, Victoria, and Tasmania. A genus of 300 species; 1 species in Western Australia; 0 endemic to Western Australia.
Etymology. From the Greek for "an ear of corn, generally a plant"; the word was also used for S. germanica in both Greek and Latin.