Westringia Sm.

Scientific Description

Common name. Westringias. Family Lamiaceae.

Habit and leaf form. Shrubs; evergreen; bearing essential oils. Plants unarmed. Leaves cauline. Plants with neither basal nor terminal concentrations of leaves. Young stems tetragonal. To 0.3–1.2 m high. Leptocaul. Leaves small to medium-sized; not fasciculate; whorled; 3–5 per whorl; petiolate, or subsessile; aromatic, or without marked odour; simple; epulvinate. Leaf blades entire; rolled; linear; one-veined, or pinnately veined; cross-venulate; cordate to cuneate at the base, or rounded at the base. Mature leaf blades adaxially glabrous, or scabrous; abaxially pilose (appressed hairy). Leaves without stipules. Leaf blade margins entire; revolute. 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, or in racemes (-like), or in heads (globular). Inflorescences terminal, or axillary; racemelike on leafy branches, the partial inflorescences 1-flowered. Flowers sessile, or subsessile; bracteate (very small and sometimes obsolete); 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; regular to unequal but not bilabiate; non-fleshy; persistent; with the median member posterior. Calyx lobes triangular. Corolla present; disguisedly 5; 1 -whorled; gamopetalous; blunt-lobed; imbricate; bilabiate (the upper lip erect and 2-lobed, the lower lip spreading and 3-lobed); hairy abaxially; hairy adaxially; with contrasting markings; white (with purple markings), or white. Corolla lobes obovate. 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 including staminodes (reduced to a connective). Staminodes 2; representing the anterior-lateral pair. Stamens 2; not didynamous, not tetradynamous; all more or less similar in shape; reduced in number relative to the adjacent perianth; fertile stamens representing the posterior-lateral pair; oppositisepalous; all alternating with the corolla members. Anthers separate from one another; basifixed; versatile, or non-versatile; dehiscing via longitudinal slits; introrse; unilocular; tetrasporangiate; appendaged (with a shortly produced connective). 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. Styles 1; simple; from a depression at the top of the ovary (the ovary deeply lobed); apical. Stigmas 1; 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. Embryo well differentiated. Cotyledons 2. Embryo straight.

Special features. The flowering nodes separated by extended internodes. 1 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 bilobed (erect); upper (adaxial) lip of the corolla not concave. Lower (abaxial) lip of the corolla 3 lobed (spreading); not concave. Stamens descending. The appendages of the staminode anthers linear.

Geography, cytology, number of species. Native of Australia. Endemic to Australia. Australian states and territories: Western Australia, South Australia, Queensland, New South Wales, Victoria, and Tasmania. South-West Botanical Province. A genus of ca. 25 species; 4 species in Western Australia; 2 endemic to Western Australia.

Etymology. After Johan Peter Westring (1753–1833), physician to the King of Sweden, writer on lichens.