iridaceous,a.Bot.|aɪərɪˈdeɪʃəs| [f. L. īrid-(seeprec.) + -aceous.] Related to plants of the genus Iris; belonging to the natural order Iridaceæ. 1851Glenny Handbk.Fl.Gard. 264 A family of showy iridaceous bulbs, requiring a frame or greenhouse.1855in Mayne Expos.Lex.