Southern Benin has a dry subequatoriai climate with a rainfall gradient from 850 mm in the west to 1 500 mm in the east, the geomorphology is varied and the vegetation has been subjected to strong human influence. There are numerous plant formations, namely: 1, forest islands which are probably relics of the primitive vegetation and include (a) dense semi-deciduous forests of several types, (b) swamp forests of two types, (c) periodically flooded forest of two types, (d) Lophira lanceolata (Hutchinson Dalziel, 1954-72) woodlands and (e) mangrove swamps; 2, formations which are probably derived and include (a) thickets of several types, (b) tree savannas and shrub savannas, (c) grassy savannas and prairies varying according to soil characteristics and (d) halophytic grasslands; and 3, floating vegetation on fresh-water lakes.
