A new species of Camchaya (Asteraceae, Vernonieae) from Thailand

Camchaya thailandica Bunwong, Chantar. & S.C.Keeley, sp. nov. from Phu Phrabat Historical Park, Udon Thani, Thailand is described as a new species. Plant of this new species are similar to C. gracilis (Gagnep.) Bunwong & H.Rob. but differ inovate phyllaries without margin spines, 10-ribbed achenes, and broadly ovate leaves. This species is a rare endemic known only from the type collection and probably confined to open areas of sandstone hills in Udon Thani province.