ANATOMY OF THE GYNOECIUM IN TWO SPECIES OF BAKERIDESIA (MALVACEAE)

A B S T RA CT Structure of the gynoecium is described in two species of Bakeridesia, subgenus Bakeridesia (Malvaceae, tribe Malveae). The dorsal wall of each carpel bears a winglike projection with a marginal pair of pubescent, bluntly dentate wings. The projection arises as a single, solid ridge of tissue after the ovules are initiated and after the ventral carpellary margins are fused with the receptacle. Two multiseriate layers of fiber-sclereids line each locule and continue into the winglike projection where they are separated by parenchyma. Gynoecial vascularization is described in detail. The richly vascularized carpels are supplied by five traces: a median dorsal trace, which bifurcates into two dorsal bundles; two lateral traces; and two ventral traces. Adjacent ventral traces, lateral traces, and septal bundles are fused-i.e., they are held in common by neighboring carpels. The presence of lateral carpellary traces may be a primitive character in the tribe Malveae. BAKERIDESIA HOCHR. (Malvaceae, tribe Malveae) is a small neotropical genus of arborescent shrubs which in many characters appears unspecialized relative to other genera of Malveae. The genus comprises two subgenera (Hochreutiner, 1920b; Bates, 1973): the predominantly North American subgenus Bakeridesia, which possibly deserves generic status; and the South American subgenus Dipteron, which is morphologically intermediate between subgenus Bakeridesia and the genus Abutilon. In the present paper consideration is given to the morphology and anatomy of the gynoecium and fruit in two species of subgenus Bakeridesia: B. integerrima (Hooker)