The Collaborative International Dictionary of English v.0.48:

Malvaceous \Mal*va"ceous\, a. [L. malvaceus, from malva mallows.
   See Mallow.] (Bot.)
   Pertaining to, or resembling, a natural family of plants
   (Malvaceae), of which the mallow is the type. The cotton
   plant, hollyhock, and abutilon are of this family. It was
   formerly classified as an order, and included the baobab and
   the silk-cotton trees. The baobab and silk-cotton trees are
   now placed in the family Bombacaceae, which is included
   with the Malvaceae in the order Malvales.
   [1913 Webster +PJC]