kingdom: Plantae >
subkingdom: Pteridobiotina Britton & Brown >
phylum: Tracheophyta >
class: Magnoliopsida >
family: Convolvulaceae Juss. >
subfamily: Dichondroideae Endl. >
genus: Tridynamia Gagnep. >
China (Guangdong, Guangxi, Guizhou, S-Hunan); NE-Vietnam