Orontioideae is a subfamily of flowering plants in a family. One to two species of skunk cabbage from North America and Asia belong to that subfamily. That subfamily and Ageratum genus are not in the same family. Arisaema candidissimum lettuce is a member of the original family.
Lysichiton is a genus in the family Araceae. 
Ageratum ( ), (whiteweed in the USA), is a genus of 40 to 60 tropical and warm temperate flowering annuals and perennials from the family Asteraceae, tribe Eupatorieae. 
 The subfamily consists of three genera namely, "Lysichiton" (one to two species of skunk cabbage from North America and Asia), "Orontium" (golden club, one living species from eastern North America and two extinct species known from fossils), and "Symplocarpus" (several species of skunk cabbage from North America and Asia). 
Arisaema candidissimum is a species of flowering plant in the arum family (Araceae), originating in western China (Tibet, Sichuan, Yunnan). 
