I do believe this is the same "form" of
Markhamia lutea commonly sold here in Florida, USA.
It appears to be different than the "forms" available in California, USA, which have larger flowers usually splashed or lined with red in the throat. The "splashed" species was originally sold as
M. platycalyx; the "lined" form was sold as
M. hidebrandtii (M. hildebrandtiana). I'm not a botanist, but the lumping together of the three "species" into
M. lutea has indeed created much confusion, especially in the US nursery trade.
I will try to post some pictures of the three "forms" soon.
Regards--
Ken Greby
Palmetto Bay, Florida USA