This name is a synonym of Musineon divaricatum (Pursh) Nutt..
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 50095789) with original publication details: Fl. Amer. Sept. 2: 732 1814.
This name record (from Tropicos) was not included in version 1 of The Plant List. It is possible the same name was included from a different data source, to check this you can search for Seseli divaricatum in version 1 of The Plant List.