 Trillium grandiflorum was originally described as T. rhomboideum var. grandiflorum by André Michaux in his 1803 work Flora Boreali @-@ Americana . T. rhomboideum is now a synonym of the closely related species T. erectum . T. grandiflorum was first treated as a species by Richard Anthony Salisbury only two years later . The species was traditionally placed in the subgenus Trillium , but recent work has shown the phylogeny of this grouping to be paraphyletic . Since then no phylogeny of the genus has garnered much agreement ( The other subgenus , Phyllantherum , includes sessile @-@ flowered species ) . T. grandiflorum is , alongside the western T. ovatum , one of the closer relatives to the subg . Phyllantherum members . 
