Pseudanthia are characteristic of the daisy and sunflower family (Asteraceae or Compositae). Their flowers are either "ray flowers" or "disk flowers". The disk flowers in the center of the pseudanthium look like the centre of a normal flower. Flowers on the periphery have one large petal. This sytem is unique to this family. Either ray or disk flowers may be absent in some species: "Senecio vulgaris" lacks ray flowers and "Taraxacum officinale" lacks disk flowers. The pseudanthium has a whorl of bracts below the flowers.