Thanks, Monique and Stewart. With all the hybrid and cultivated varieties
around, especially the doubles, I wondered if there was a reliable distinction
for the vegetative parts as well as the shape of the receptacles.

(And then there's Ratibida and Echinacea, although the latter at least
isn't (usually) yellow.)

(And yesterday I saw some chrysanthemums with yellow ray florets and a
solid black disk.)