Leucas

Annual or perennial herbs or subshrubs. Leaves thin or thick-textured, entire or toothed. Inflorescences usually simple, of few to many, spaced or fairly crowded verticils; verticils 2-many-flowered, often in glomerate clusters; bracts leaf-like, often smaller towards apex of inflorescence; bracteoles linear, ascending, small or conspicuous. Calyx shorter or longer than corolla tube, tubular or tubular-campanulate, rarely inflated, 10-nerved, straight or curved, sometimes oblique at mouth; teeth 5-10, equal or unequal, often spine-tipped. Corolla bilabiate, white; tube tubular, widening above, sometimes shortly constricted at base, annular-pilose or annular-papillose within, rarely glabrous; upper ascending or spreading, concave or flattish, entire or rarely emarginate or 2-lobed, longer than, subequal to or shorter than lower lip, usually with stiff brush-like hairs; lower lip spreading or deflexed, 3-lobed, median lobe the largest. Stamens 4, didynamous, lower pair longer than upper, ascending under the upper lip, included or shortly exserted; anthers approximate in pairs, 2-thecous with the thecae divaricate and finally confluent. Style terete, ascending under upper lip, unequally 2-lobed at apex. Nutlets ovoid-triquetrous, smooth, obtuse or somewhat flattened at apex. x = 11, 7 (polyploidy).