Lippia L.

Erect bushes, shrubs, undershrubs, or subshrubs, rarely trees, glabrous or variously pubescent with simple trichomes, often hirsute or tomentose, sometimes functionally dioecious, in some grassland regions with herbaceous branches issuing from a basal or subterranean woody xylopodium. Leaves decussate-opposite or ternate, rarely alternate or in 4's, simple, deciduous, entire to variously toothed or lobed, exstipulate, petiolate or sessile, flat or rugose above, thin-membranous to heavy-coriaceous, mostly penninerved. Inflorescences indeterminate, centripetal, spicate or capitate, solitary or fascicled in the leaf-axils or aggregate in axillary or terminal corymbs or panicles, the spikes mostly contracted into heads or cylin-dric, not usually conspicuously elongating in fruit, densely-flowered, bractlets conspicuous, not caducous, decussate or many-ranked, often folded, sometimes concave or flat, imbricate, sometimes forming an involucre, mostly large and ovate or lanceolate, often decreasing in size toward the apex of the spike, often accrescent after anthesis. Flowers small, sessile, borne singly in the axils of the bracts or bractlets, often more or less 4-ranked, often dimorphic, in some species staminate plants have flowers with well-developed anthers and aborted or non-functional ovary, while carpellate plants have flowers with no stamens or only occasionally 1 or 2 aborted stamens; calyx small, membranous, ovoid-campanulate or compressed and often 2-carinate or-alate, sometimes 2-lipped, the rim 2-or 4-fid or 4-dentate; corolla white or variously colored, hypocrateriform or infun-dibular, irregular, the tube cylindric, straight or incurved, slender, slightly ex-serted from the calyx or rarely elongate, equal in diameter throughout or ampliate above, the limb oblique, usually spreading, somewhat 2-lipped, 4-parted, the lobes broad, often retuse apically, the posterior lobe entire, emarginate, or even bifid to about the middle, the lateral lobes exterior, the anterior lobe often larger; stamens 4, didynamous, inserted at about the middle of the corolla-tube; included or slightly exserted, sometimes only 1 or 2 present or completely absent on car-pellate plants, the anthers ovate, unappendaged, the thecae parallel, often aborted or absent on pistillate plants; gynoecium often aborted or non-functional on staminate plants, gynoecium syncarpous, the ovary globose, 2-loculed, the ovules 1 per locule, basal and erect or affixed laterally near the base; the style single, often short, the stigma single, incrassate or capitate, oblique or recurved. Fruits small, dry, ovoid, included by the fruiting-calyx and sometimes adnate to it, dividing into 2 pyrenes or nutlets at maturity, the pericarp papery and hard, the exocarp membranous and rarely distinct from the pyrenes; seeds without endo-sperm.