Hibiscus flower

Why this flower can be said of hibiscus flowers, while if we see the shape is not at all menghuoai shoes or so.
Although the look of this flower is not at all like a shoe, but one source states the reason why this flower is named after the hibiscus because once in India, this flower is used as shoe polish and eventually known as hibiscus flower in Indonesia. here is an explanation of one of the references I read.

Before blooming:

Hibiscus flowers have meaning and various colors.