Sequence analyses of the plastid genes atpB and rbcL support an expanded order Malvales consisting of three monophyletic groups: Malvaceae s.l. (including Sterculiaceae, Tiliaceae, and Bombacaceae), a bixalean clade (Bixaceae, Diegodendraceae, and Cochlospermaceae), and a cistalean clade (Cistaceae, Dipterocarpaceae, Sarcolaenaceae, Muntingiaceae, and Thymelaeaceae). Sphaerosepalaceae and Neuradaceae also fall in the malvalean clade, but their position is not resolved. The traditional delimitations of Malvaceae, Sterculiaceae, Tiliaceae, and Bombacaceae are artificial. As a consequence, they are better included in a single family Malvaceae. The more broadly defined Malvaceae are tentatively subdivided into 12 tribes that are based on molecular, morphological, and biogeographical data. The first three tribes, Byttnerieae, Lasiopetaleae, and Theobromeae, are difficult to delimit and may be united as byttnerioids. Grewieae, which include most of the former Tiliaceae, and Hermannieae are embedded within the byttnerioids in the molecular analysis. Tilieae are much reduced and isolated. Helictereae include Mansonia and Triplochiton, in addition to the traditional genera, which indicates that apocarpy evolved at least twice within Malvaceae. The position of the Durio alliance and of Mortoniodendron remains problematic. An advanced clade includes Brownlowieae, Sterculieae, Dombeyeae, Bombaceae, and Malveae, of which the latter two tribes require further research to find evidence of monophyly.

Key words: Bombacaceae, Malvaceae, molecular systematics, Sterculiaceae, Tiliaceae