It looks like it's in the Malvaceae or Hibiscus family. I t could infact be a Hibiscus species. Perhaps it's a herbacious species from the higher elevations.
It looks to me like a "Hibiscus Tree"...known as Hau in Hawaiian and prevalent throught the S. Pacific. The flower starts out yellow, fades, drops and dies a lovely rosey peach color...1 day life span. Could that be it?
