Zinnia flowers are interesting. As members of the aster or sunflower family (Asteraceae or Compositae), they have composite flowers—flowers made up of many little flowers. There are actually two different types of flowers on each single” zinnia flower. Around the outside are ray flowers which have, in the case of the flower shown here, a single petal. Sometimes they have multiple petals, making the overall compound flower “double.” Then, in the center of the compound flower are disk flowers. In the picture here, these disk flowers have orange in their corolla lobes. The little question mark filaments at the base of the ray flowers are their stigmata.