Source : Webster's Revised Unabridged Dictionary (1913)

Petaloideous \Pet`al*oid"e*ous\, a. (Bot.)
   Having the whole or part of the perianth petaline.

   {Petaloideous division}, that division of endogenous plants
      in which the perianth is wholly or partly petaline,
      embracing the {Liliace[ae]}, {Orchidace[ae]},
      {Amaryllide[ae]}, etc.