The Collaborative International Dictionary of English v.0.48:

dusty \dust"y\ (d[u^]st"[y^]), a. [Compar. Dustier
   (d[u^]st"[i^]*[~e]r); superl. Dustiest
   (d[u^]st"[i^]*[e^]st).] [AS. dystig. See Dust.]
   1. Filled, covered, or sprinkled with dust; clouded with
      dust; as, a dusty table; a dusty attic; also, reducing to
      dust.
      [1913 Webster]

            And all our yesterdays have lighted fools
            The way to dusty death.               --Shak.
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   2. Like dust; of the color of dust; as, a dusty white.
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   Dusty miller (Bot.), a plant (Cineraria maritima); -- so
      called because of the ashy-white coating of its leaves.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Cineraria maritima
    n 1: stiff much-branched perennial of the Mediterranean region
         having very white woolly stems and leaves [syn: dusty
         miller, Senecio cineraria, Cineraria maritima]