This name is a synonym of Ditaxis humilis f. laevis (A.Gray ex Torr.) B.L.Turner.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 15109) with original publication details: Linnaea 34: 147 1865.
This name was in version 1 of The Plant List, record kew-15109, and has not been changed.