Oldenlandia purpurea var. tenuifolia (Nutt.) A.Gray Dataset GBIF Backbone Taxonomy Rank VARIETY Classification kingdom Plantae phylum Tracheophyta class Magnoliopsida order Gentianales family Rubiaceae genus Houstonia species Houstonia longifolia Name Homonyms Oldenlandia purpurea var. tenuifolia (Nutt.) A.Gray ex Chapm. Oldenlandia purpurea var. tenuifolia (Nutt.) A.Gray