The Collaborative International Dictionary of English v.0.48:

Efflorescent \Ef`flo*res"cent\, a. [F. efflorescent, L.
   efflorescens, -entis, blooming, p. pr. of efflorescere. See
   Effloresce, v. i.]
   1. That effloresces, or is liable to effloresce on exposure;
      as, an efflorescent salt.
      [1913 Webster]

   2. Covered with an efflorescence.
      [1913 Webster]