What is (a) Having an equal number of parts in the successive circles of floral organs; -- said of flowers. (b) Having a likeness in the form and size of floral organs of the same kind; regular called?

symmetrical — (Bot.) (a) Having an equal number of parts in the successive circles of floral organs; -- said of flowers. (b) Having a likeness in the form and size of floral organs of the same kind; regular. (Webster's 1913.)

Sources