Source : Webster's Revised Unabridged Dictionary (1913)

Rockrose \Rock"rose`\, n. (Bot.)
   A name given to any species of the genus {Helianthemum}, low
   shrubs or herbs with yellow flowers, especially the European
   {H. vulgare} and the American frostweed, {H. Canadense}.

   {Cretan rockrose}, a related shrub ({Cistus Creticus}), one
      of the plants yielding the fragrant gum called ladanum.