widely recognized.
* Trillium govanianum, first described in 1839, was segregated into genus Trillidium in 1850. However, the name Trillidium govanianum is not widely recognized.
* Trillium undulatum, first described in 1801, was segregated into genus Trillidium in 2018, but the name Trillidium undulatum is controversial and not widely recognized.

Phylogenetic analysis places Trillidium govanianum and Trillidium undulatum together in a clade with high support. However, since