Source : Webster's Revised Unabridged Dictionary (1913)

Umbilicate \Um*bil"i*cate\, Umbilicated \Um*bil"i*ca`ted\, a.
   [L. umbilicatus. See {Umbilic}.]
      (a) Depressed in the middle, like a navel, as a flower,
          fruit, or leaf; navel-shaped; having an umbilicus; as,
          an umbilicated smallpox vesicle.
      (b) (Bot.) Supported by a stalk at the central point.

Source : WordNet®

umbilicate
     adj : depressed like a naval