Canthium

Canthium species are predominantly found in Southeast Asia, especially in Thailand and the Philippines.[1] A small number of species is found in India, Sri Lanka, and Bangladesh. Only a limited number of species is found on the African continent, especially in Southern and East Africa.[2]

Canthium was named by Jean-Baptiste Lamarck in 1785 in Encyclopédie Méthodique.[3] The name is a latinisation of "kantankara", a Malayalam name from Kerala for Canthium coromandelicum. Kantan means "shining" and kara means "a spiny shrub".[4] The biological type for the genus consists of specimens originally described by Jean-Baptiste Lamarck as Canthium parviflorum[5] but this species is now included in Canthium coromandelicum.[1] Canthium is a member of Vanguerieae, a tribe that is monophyletic and easily recognized morphologically, but in which generic boundaries were, for a long time, very unclear.[6] Canthium was especially problematic, and until the 1980s, it was defined broadly and known to be polyphyletic. Psydrax was separated from it in 1985,[7] as was Keetia in 1986.[8] These were followed by Pyrostria and Multidentia in 1987.[9][10] The subgenus Afrocanthium was raised to generic rank in 2004,[11] followed by Bullockia in 2009.[12] A few species were transferred to Canthium from Rytigynia and other genera in 2004.[11] The genus was further reduced by the transfer of species to Peponidium and Pyrostria.[13] In 2016, two Canthium species endemic to the Philippines were transferred to a genus of their own, Kanapia.[14] The final circumscription of Canthium will remain in doubt until phylogenetic studies achieve greater resolution for the clade containing Canthium coromandelicum and its closest relatives.