This name is a synonym of Xylorhiza tortifolia (Torr. & A.Gray) Greene.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 028550E3-C89D-4417-B923-3A6D9FB36A2C) with original publication details: 1963.
This name record (from TICA) 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 Machaeranthera tortifolia in version 1 of The Plant List.