Bryum lacustre var. arnellii (Kindb.) Kindb. Dataset GBIF Backbone Taxonomy Rank VARIETY Classification kingdom Plantae phylum Bryophyta class Bryopsida order Bryales family Bryaceae genus Ptychostomum species Ptychostomum knowltonii Name Homonyms Bryum lacustre var. arnellii (Kindb.) Kindb. Bryum lacustre subsp. arnellii Kindb.