Everything about the plant reminds me of Iochroma australe which I once had Myriam, so Solanaceae seems most likely. The flowers look like a cross between Brugmansia and Cobaea!
I'm looking .. seem to have lost the tropical plants site I once used.
Solandra looks similar ..
http://ceb.wikipedia.org/wiki/...
http://plantillustrations.org/...
Look at fig. 43 on this pdf .. although I can't work out if there's an example given!
http://www.anatomiavegetal.ib....
The google link to the pdf offered a translation, there's no diagrams although the pages and figure no.'s are given.
http://translate.google.co.uk/...
I picked out an example of Bignoniaceae after #45 but that looks less likely.
