Merremia sp.
Pamela Slate (Tue, 27 Sep 2011 16:33:11 PDT)

Dear Uli,
That would be Merremia aurea, native to southern Baja, California.  Commonly known here as Yuca (not a misspelling!) Vine, it freezes back in winter and regrows in spring, blooming throughout the summer. 

Good luck growing it!

Best,
Pamela

Pamela Slate
P.O. Box 5316
Carefree AZ 85377