The Collaborative International Dictionary of English v.0.48:

Artemisia \Ar`te*mi"si*a\ ([aum]rt[-e]"m[i^]zh"[i^]*[.a] or
   [aum]rt[-e]"m[i^]sh"[i^]*[.a]), n. [L. Artemisia, Gr.
   'Artemisi`a.] (Bot.)
   A genus of plants including the plants called mugwort,
   southernwood, and wormwood. Of these Artemisia absinthium,
   or common wormwood, is well known, and Artemisia tridentata
   is the sage brush of the Rocky Mountain region.
   [1913 Webster]

WordNet (r) 3.0 (2006):

artemisia
    n 1: any of various composite shrubs or herbs of the genus
         Artemisia having aromatic green or greyish foliage