The fruit morphology of 18 taxa representing seven genera of the family Polygonaceae in West Africa was investigated using Scanning Electron Microscopy. The achenes are trigonous, lenticular, globose, subglobose, heart shaped, ovoid or cone like. Sizes range from 0.12 x 0.10 cm2 in Polygonum plebeium to 7.87 x 0.58 cm2 in Afrobrunnichia erecta. Colours are brown to black. The cells are isodiametric in Polygonum plebeium, irregular in Afrobrunnichia erecta, Antigonon leptopus, Harpagocarpus snowdenii and polygonal in other species. The walls are straight, curved, or undulate and are either raised or depressed. A. erecta is characterized with deeply sinuate lateral walls. Cell surface may be smooth or tuberculate or fibrillate in the family, usually covered with wax deposits. The combination of these characters is mainly taxonomically useful at the tribal level and rarely at the specific or infra specific level for the delimitation of the taxa.