A taxonomic synopsis of Heliotropiaceae (Boraginales) in Thailand

A synopsis of Heliotropiaceae in Thailand is presented together with the taxonomic history, identification keys, distribution, phenology, herbarium specimen citations and diagnostic characters of each species. The taxonomic character of the family is of terminal style with a conical stigma structure forming a basal ring around the style. There are 12 species: five species each in Euploca and Tournefortia and two species in Heliotropium. Three species are newly recorded in Thailand, Euploca ovalifolia, Tournefortia hookeri and T. montana. Lectotypes are selected for T. boniana and T. tetrandra var. angustifolia