NIGERIA is in all respects, a tropical country with average temperatures of around 800F. prevalent almost everywhere throughout the year, with some amelioration in the highland areas of the Jos Plateau, Adamawa, and the Southern Cameroons. Rainfall is variable both in amount and incidence, ranging from about 20 inches a year in the extreme north to over 300 inches in the coastal areas of the Cameroons. The duration of the wet season lessens and the dry season increases in length from South to North. In the northern parts, rain falls during only three months of the year, but throughout the country there is usually sufficient for crop cultivation. With varying rainfall and soil conditions the vegetation ranges from mangrove swamp in the south through tropical rain forest, the home of mahogany, iroko, sapale, obeche and other famous tropical hardwoods to the parkland and thorn bush scrub in the North. There is no desert country. The river Niger with its major tributary, the Benue, trisects Nigeria -and together with a portion of Lake Chad in the north east corner of the country form the major waterways of the interior.