Species of the genus Merremia (Convolvulaceae) from State of Bahia were surveyed, and their pollen grains were studied by usual methods. Nine taxa were recorded: M. aegyptia (L.) Urb., M. cissoides (Lam.) Hallier f., M. digitata (Spreng.) Hall. f. var. digitata, M. digitata var. ericoides (Meissn.) Austin & Staples, M. dissecta (Jacq.) Hall. f. var. edentata (Meisn.) O'Donell, M. flagellaris (Choisy) O'Donell, M. macrocalyx (Ruiz et Pav.) O'Donell, M. tomentosa (Choisy) Hall. f. and M. umbellata (L.) Hall. f. In M. digitata var. digitata and M. flagellaris, the pollen grains presented irregular colpi and with three and six long colpi. Thick apertural membrane was observed in M. aegyptia, M. cissoides, M. digitata var. ericoides; presence with opercules in M. aegyptia, M. cissoides and M. digitata var. ericoides pollen grains. Six-aperturated pollen grains are zonocolpate (in M. umbellata) or pantocolpate (in M. digitata var. digitata, M. digitata var. ericoides and M. flagellaris); more than one apertural type can be found grains in the same specimen. The palinological data corroborate the placement of M. aegyptia, M. dissecta var. edentata and M. macrocalyx in M. sect. Schizips, M. umbellata in M. sect. Xanthips and other ones in M. sect. Cissoides. In the latter section, excluding M. tomentosa, all species belong to the complex M. digitata, in which they are not well delimitated.
Convolvulaceae; Merremia; Palinology; Bahia; Brazil
