A taxonomic synopsis of Heliotropiaceae and new combinations in Heliotropium from Thailand Author Rueangsawang, Kanokorn https://orcid.org/0000-0003-1595-1514 Department of Biology, Faculty of Science, Ramkhamhaeng University, Bangkok 10240, Thailand Author Chantaranothai, Pranom https://orcid.org/0000-0002-5065-6169 Applied Taxonomic Research Center, Department of Biology, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand & Royal Botanic Gardens, Kew, Richmond, Surrey TW 9 3 AE, UK pranom@kku.ac.th text PhytoKeys 2023 2023-09-21 232 189 210 http://dx.doi.org/10.3897/phytokeys.232.103647 journal article http://dx.doi.org/10.3897/phytokeys.232.103647 1314-2003-232-189 650B1993F8DC52FBBF49899A6B6A4D6F 3. Heliotropium hookeri (C.B.Clarke) Rueangs. & Chantar. comb. nov. Tournefortia hookeri C.B.Clarke, Fl. Brit. India 4: 147. 1883. Tournefortia viridiflora Gamble, Darjeeling List: 57. 1878. nom.illeg. Type . Sikkim, Himalayas, Hooker s.n . ( holotype K [K000998133!]). Distribution. East Himalaya, Myanmar, Thailand (Fig. 1H ). Ecology. Deciduous forest, flowering and fruiting in June. Specimens examined. Thailand , Northern : Chiang Mai , Ban Pa Kar , Samoengtai , Samoeng , 1,424 m alt., 26 June 2008 , Jatupol 08 - 275 (QBG) . Diagnostic characters. Heliotropium hookeri is newly recorded for Thailand due to a specimen of this distinctive species seen from QBG. This species is recognisable in the leaves being broadly ovate with dense golden brown tomentose hairs on the lower surface and loosely dichotomous cymose.