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]