Placoneis exigua (Gregory) Mereschkovsky Dataset GBIF Backbone Taxonomy Rank SPECIES Classification kingdom Plantae phylum Bacillariophyta class Bacillariophyceae order Cymbellales family Cymbellaceae genus Placoneis species Placoneis exigua Name Homonyms Placoneis exigua (Gregory) Mereschkovsky, 1903 Placoneis exigua (W.Greg.) Mersechkowsky