Xanthium californicum var. rotundifolium Widder Dataset GBIF Backbone Taxonomy Rank VARIETY Classification kingdom Plantae phylum Tracheophyta class Magnoliopsida order Asterales family Asteraceae genus Xanthium species Xanthium strumarium Name Homonyms Xanthium californicum var. rotundifolium Widder Xanthium californicum subsp. rotundifolium Widder