Rheum undulatum var. latifolium Metzg. Dataset GBIF Backbone Taxonomy Rank VARIETY Classification kingdom Plantae phylum Tracheophyta class Magnoliopsida order Caryophyllales family Polygonaceae genus Rheum species Rheum rhabarbarum Name Homonyms Rheum undulatum var. latifolium Metzg. Rheum undulatum var. latifolium Metzg. ex Alef.