The Collaborative International Dictionary of English v.0.48:

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.
          [1913 Webster]

WordNet (r) 3.0 (2006):

umbilicate
    adj 1: depressed like a navel