Melissa

Perennial herbs; branchlets 4-angled, hairs simple, often glandular. Leaves opposite, petiolate, entire, margin serrate. Inflorescence a thyrse, with few–many-flowered cymes in axils of leaves or leaf-like bracts; internodes of inflorescence apparent. Calyx 2-lipped, 13-veined; abaxial lip 2-toothed, adaxial lip flattened, 3-toothed; corolla 2-lipped, tube curved and dilated above the middle, abaxial lip with mid-lobe broadly oblong and 2 shorter lateral lobes, adaxial lip short, 2-lobed; stamens 4, fertile, inserted near throat of corolla, anthers with locules strongly divergent, both fertile, not exserted; ovary deeply 4-lobed, style gynobasic, stigma terminal, 2-fid. Mericarps oblong-ovoid, unkeeled.