Is this Hibiscus pernambucensis or even Hibiscus for that matter?
Hibiscus?
It looks like a Hibiscus tiliaceus, although mine have a dark red or burgundy throat. Otherwise, the leaves appear to match plus the yellow colour. They grow along the coastline here and at the back of mangroves. They're sometimes included with mangroves in plant lists. Some of the common names are Beach Hibiscus and Coastal Cottonwood. There a 'red' variety which has reddish leaves and the flowers are darker.
Thanks for the information. This specimen is actually located along the Florida coastline near many mangroves at the Fairchild Tropical Botanic Gardens. I will have to visit area again. Here is a closer view of the flower.
Yes, it is Hibiscus tiliaceus. They usually, but not always, have a brownish-red to maroon spot at the base of the flower.