This name is a synonym of Hydrostemma kunstleri (Ridl.) B. C. Stone.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 22600171) with original publication details: Minnesota County Biol. Surv. Map Ser. 1922.
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 Barclaya kunstleri in version 1 of The Plant List.