 A phylogenetic analysis of various eastern Asian and eastern North American disjunct Suillus species revealed that S. sibiricus forms a well @-@ supported clade with S. americanus and S. umbonatus ; these relationships are corroborated by a previous analysis ( 1996 ) , which used a larger sampling of Suillus species to determine taxonomic relationships in the genus . Within this clade , S. umbonatus and U.S. S. sibiricus can be separated from the rest of the group . However , the phylogenetic relationships among the tested isolates determined from different methods of analysis are not always consistent and could not be established with confidence . In general , there is little phylogenetic divergence detected in this clade . 
