Canthium
Canthium is a genus of flowering plants in the family Rubiaceae. They are shrubs and small trees. The leaves are deciduous and the stems are usually thorny.
Distribution
Canthium species were predominantly found in Southeast Asia, especially in Thailand and the Philippines. A small number of species was found in India, Sri Lanka, and Bangladesh. Only a limited number of species were found on the African continent, especially in Southern and East Africa.
Taxonomy
Canthium was named by Jean-Baptiste Lamarck in 1785 in Encyclopédie Méthodique. The name is a latinisation of "kantankara", a Malayalam name from Kerala for Canthium coromandelicum. Kantan means "shining" and kara means "a spiny shrub". The biological type for the genus consists of specimens originally described by Jean-Baptiste Lamarck as Canthium parviflorum but this species is now included in Canthium coromandelicum. 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. Canthium was especially problematic, and until the 1980s, it was defined broadly and known to be polyphyletic. Psydrax was separated from it in 1985, as was Keetia in 1986. These were followed by Pyrostria and Multidentia in 1987. The subgenus Afrocanthium was raised to generic rank in 2004, followed by Bullockia in 2009. A few species were transferred to Canthium from Rytigynia and other genera in 2004. The genus was further reduced by the transfer of species to Peponidium and Pyrostria. In 2016, two Canthium species endemic to the Philippines were transferred to a genus of their own, Kanapia. 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.
Species
, Plants of the World Online recognises the following species:Canthium aciculatum Ridl.Canthium angustifolium Roxb.Canthium arboreum VidalCanthium armatum Canthium aurantiacum Merr. & L.M.PerryCanthium berberidifolium GeddesCanthium bipinnatum Merr.Canthium brunneum Merr.Canthium bugoyense Canthium calvum CraibCanthium cambodianum Pit.Canthium campanulatum ThwaitesCanthium cavaleriei H.Lév.Canthium ciliatum KuntzeCanthium coffeoides Pierre ex Pit.Canthium congestiflorum Ridl.Canthium cordatum DillwynCanthium coromandelicum AlstonCanthium depressinerve Ridl.Canthium ellipticum Merr.Canthium fenicis Merr.Canthium ferrugineum CraibCanthium filipendulum Pierre ex Pit.Canthium fraternum Miq.Canthium glaucum HiernCanthium gracilipes KurzCanthium hainanense LantzCanthium hirtellum Ridl.Canthium hispidonervosum C.M.EvrardCanthium horridulum CraibCanthium horridum BlumeCanthium inerme KuntzeCanthium korthalsianum Miq.Canthium kuntzeanum BridsonCanthium laeve Teijsm. & Binn.Canthium lasianthoides Miq.Canthium libericum Dinkl.Canthium longipes GeddesCanthium lucidum R.Br.Canthium macrocarpum ThwaitesCanthium malayense K.M.WongCanthium megacarpum Merr.Canthium megistocarpum Merr. & L.M.PerryCanthium merrillianum Mabb.Canthium mite Bartl. ex DC.Canthium molle King & GambleCanthium moluccanum Roxb.Canthium oblongum Kaneh.Canthium obscurum Canthium oliganthum Boerl.Canthium oligocarpum HiernCanthium parvifolium Roxb.Canthium paucinervium Merr.Canthium pedunculare Cav.Canthium perakanthus ined.Canthium polyanthum Miq.Canthium puberulum Thwaites ex Hook.f.Canthium quadratum CraibCanthium rheedei DC.Canthium sarcocarpum Merr.Canthium sarmentosum CraibCanthium scabridum Ridl.Canthium scandens BlumeCanthium schlechterianum Merr. & L.M.PerryCanthium simile Merr. & ChunCanthium sordidum BullockCanthium spirostylum Miq.Canthium stellulatum CraibCanthium strigosum CraibCanthium strychnoides CraibCanthium subaureum CraibCanthium subcapitatum Merr.Canthium suberosum CoddCanthium subsessilifolium Merr.Canthium tavoyanum Merr.Canthium thonningii Canthium travancoricum Bedd.Canthium trichophorum Quisumb. & Merr.Canthium umbelligerum Miq.Canthium vanwykii Tilney & KokCanthium villarii VidalCanthium violaceum Zoll. & Moritzi