Taxonomic studies on Parahellenia (Costaceae) in Vietnam: a new species, P. trongduyii, and a new combination, P. candida Author Chen, Juan Key Laboratory of Plant Resources Conservation and Sustainable Utilization / Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, 510650, Guangzhou, People’s Republic of China & South China National Botanical Garden, 510650, Guangzhou, People’s Republic of China Author Nguyen, Van Canh 0000-0001-9853-5510 Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh Duong Province, Vietnam & nguyenvancanh @ tdmu. edu. vn; https: // orcid. org / 0000 - 0001 - 9853 - 5510 nguyenvancanh@tdmu.edu.vn Author Nguyen, Van Khuong 0000-0002-1264-5178 Institute of Applied Technology, Thu Dau Mot University, No. 6 Tran Van On Street, Phu Hoa Ward, Thu Dau Mot City, Binh Duong Province, Vietnam & nvkhuong @ ttn. edu. vn; https: // orcid. org / 0000 - 0002 - 1264 - 5178 nvkhuong@ttn.edu.vn Author Nguyen, Khang Sinh Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Street, Hanoi, Vietnam & Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Street, Hanoi, Vietnam Author Nuraliev, Maxim S. Joint Russian-Vietnamese Tropical Scientific and Technological Center, Nguyen Van Huyen Street, Cau Giay, Hanoi, Vietnam Department of Higher Plants, Biological Faculty, M. V. Lomonosov Moscow State University, 1, 12, Leninskie Gory, 119234 Moscow, Russia Author Xia, Nianhe Key Laboratory of Plant Resources Conservation and Sustainable Utilization / Guangdong Provincial Key Laboratory of Digital Botanical Garden, South China Botanical Garden, Chinese Academy of Sciences, 510650, Guangzhou, People’s Republic of China & South China National Botanical Garden, 510650, Guangzhou, People’s Republic of China text Phytotaxa 2023 2023-01-31 583 1 72 80 http://dx.doi.org/10.11646/phytotaxa.583.1.7 journal article 53437 10.11646/phytotaxa.583.1.7 344edf21-53fc-463c-a6a5-00a0b5e277b5 1179-3163 7609199 Key to the species of Parahellenia in Vietnam 1. Leaf blade puberulent abaxially; labellum cream white...................................................................................................... P. candida - Leaf blade glabrous; labellum yellow with longitudinal orange to red markings at center ...............................................................2 2. Plants unbranched or barely branched; bract apex with a soft mucro............................................................................. P. trongduyii - Plants densely branched; bract apex with a sharp mucro ............................................................................................... P. tonkinensis