wheel-shaped

from The Collaborative International Dictionary of English v.0.48

Wheel-shaped \Wheel"-shaped`\, a.
   [1913 Webster]
   1. Shaped like a wheel.
      [1913 Webster]

   2. (Bot.) Expanding into a flat, circular border at top, with
      scarcely any tube; as, a wheel-shaped corolla.
      [1913 Webster]