Approximately 350 species of small shrubs and subshrubs from temperate Asia. They are aromatic and wiry-stemmed with opposite pairs of simple evergreen leaves and whorled spikes or heads of small, tubular, two-lipped flowers with leaf-like, but sometimes differently shaped or coloured bracts. Many species bear clusters of smaller leaves in the main leaf axils which persist when the latter are shed.
Several species are basic rock garden plants and many others deserve to be tried there or in the raised bed, scree or alpine house. Freely draining soil and plenty of sun are basic requirements. Any other cultural needs are noted in the species' descriptions. Propagation by seeds in spring or cuttings in early or late summer. The freely stem-rooting mat-formers can also by divided after flowering, early autumn or spring. (summer-flowering unless stated otherwise)