Polysiphonia nigrescens var. fucoides (Hudson) Harvey Dataset GBIF Backbone Taxonomy Rank VARIETY Classification kingdom Plantae phylum Rhodophyta class Florideophyceae order Ceramiales family Rhodomelaceae genus Vertebrata species Vertebrata spec Name Homonyms Polysiphonia nigrescens f. fucoides (Hudson) J.Agardh, 1863 Polysiphonia nigrescens var. fucoides (Hudson) Harvey