Your article is so wonderful, I expect several readers are adding hibbies to their list of "must get" or must get more" next growing season.
One observation, though, I was under the impression h. Hamabo produces a yellow flower. To satisfy my curiosity, I googled and found yellow flowers as well as white w/ red eye as you posted in your article. Curiosity not satisfied, lol.
this may be the answer to the mystery. It appears there is indeed a h. syriacus named "Hamabo" (Adina, the one you show in your article) and there is also a species hibiscus named "Hamabo", which is the one I grow. http://davesgarden.com/guides/pf/go/93850/
You mean to tell me that of all the names in the world, these botanists had to use the same name twice????? why do they want to confuse us this way!