Anisomeles is a genus of herbaceous plants in the family Lamiaceae (the mint family), order Lamiales. The genus comprises roughly 20 accepted species distributed across a broad range spanning China, the Indian Subcontinent, Southeast Asia, New Guinea, Australia, Madagascar, and various Pacific and Indian Ocean islands.
Plants in the genus are herbs with small, flat, narrow elliptic to ellipse-shaped leaves arranged in opposite pairs along the stems; leaf margins are sometimes wavy or distinctly serrated. The flowers are borne in whorled clusters and follow the typical Lamiaceae two-lipped (bilabiate) arrangement: five fused sepals and five petals forming an upper and lower lip, with the lower lip divided into three lobes — the middle lobe conspicuously longer than the two side lobes. Four stamens extend beyond the petals, and a single style sits in a depression on top of the ovary. The fruit is a schizocarp that splits into four nutlets, each containing a small seed.
The genus was first formally described in 1810 by the Scottish botanist Robert Brown in his landmark work Prodromus Florae Novae Hollandiae et Insulae Van Diemen. The name Anisomeles derives from Greek, meaning "unequal limbs" — a direct reference to the unequal lobes of the petals.
Among the most widespread species is Anisomeles indica, which ranges from China and the Himalayas through the Indian Subcontinent, Indochina, Malaysia, Indonesia, the Philippines, and New Guinea, and has been naturalized in parts of the Pacific and Caribbean. Several species are endemic to northern Australia, particularly Queensland and the Northern Territory, and were described more recently by taxonomist A.R. Bean.
Etymology
The genus name Anisomeles derives from Greek words meaning "unequal limbs," referring to the distinctly unequal lobes of the flower's petals — the middle lobe of the lower lip is much longer than the two side lobes. The name was applied by Robert Brown when he formally described the genus in 1810.
Distribution
Anisomeles is distributed across tropical and subtropical regions of Asia and the Old World tropics, with its core range in China, the Indian Subcontinent, Southeast Asia, New Guinea, Australia (especially Queensland and the Northern Territory), Madagascar, and scattered Pacific and Indian Ocean islands. Anisomeles indica, the most widespread species, has also been naturalized in Fiji, Samoa, Jamaica, and Trinidad.
Taxonomy Notes
The genus was established by Robert Brown in 1810 in Prodromus Florae Novae Hollandiae et Insulae Van Diemen, making it one of the early formally described Lamiaceae genera from the Australasian flora. Plants of the World Online recognizes approximately 20 species; the GBIF backbone currently treats a smaller number as accepted, reflecting ongoing taxonomic revision — particularly the many species described from northern Australia by A.R. Bean in recent decades.
