Houstonia tenuifolia Nuttall ex A.Gray Dataset GBIF Backbone Taxonomy Rank SPECIES Classification kingdom Plantae phylum Tracheophyta class Magnoliopsida order Gentianales family Rubiaceae genus Houstonia species Houstonia longifolia Name Homonyms Houstonia tenuifolia Nutt. Houstonia tenuifolia Nuttall ex A.Gray