Subrotunda is a South American short lived perennial although since it self seeds you are unlikely to lose it.  It was only found this century near Iguassu Falls.   It stands up straight towards a metre with lots of bright orange flowers.  Recently there has been one called white, which is not a bright white,  and has a pinkish edge to it.   In tropical areas it could become weedy.  Sun or shade doesn’t seem to matter.

Price:  $9