 Since 1998 , an American botanist , Austin Mast , has been publishing results of ongoing cladistic analyses of DNA sequence data for the <unk> <unk> . His analyses suggest a phylogeny that is very greatly different from George 's arrangement , and somewhat different from Thiele and Ladiges ' . With respect to B. violacea , Mast 's results agree with its placement near B. laricina and B. incana , placing it in a clade with these two species and B. sphaerocarpa var. <unk> ( treated at species rank as B. <unk> ) . However , Thiele 's B. subseries <unk> appears to be <unk> , as do both definitions of B. ser . Abietinae — that is , none form a natural grouping . 
