Polysiphonia nigrescens var. flaccida Aresch., 1847 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 var. flaccida Aresch., 1847 Polysiphonia nigrescens f. flaccida (Aresch.) Kylin, 1907