This name is a synonym of Lactuca lessertiana (Wall. ex DC.) Wall. ex C.B.Clarke.
The record derives from TICA
(data supplied on 2012-02-11)
which reports it as a synonym (record 7DA6C03A-80F1-4F22-99B3-59E62B5DC6F1).
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 Mulgedium lessertianum in version 1 of The Plant List.