Seed Dispersal by Motor Vehicles

developed up to the road edge. In what follows the results are described of testing samples of mud from the undersurfaces of seventy-five vehicles at University College, Ibadan, for the presence of viable seed. Two experiments were undertaken, one with forty-three samples collected in the middle of the rainy season in June 1957, the other with thirty-two samples taken 6 months later at the beginning of the dry season in early December. Shortly after collection the mud to be tested was placed on river sand in eightinch pots kept in a glasshouse. With the first experiment from each sample enough dry mud to fill a 100 cc beaker was placed on washed river sand, whilst in the second experiment 50 g of dried mud were placed on steam-sterilized sand. The standardization of the weight of mud tested and the use of sterilized instead of washed sand in the second experiment were measures designed to increase the precision of the experiment. Control pots containing sand only were included in each experiment to determine whether germinable seeds were present in the sand and to detect whether seeds were blowing into the pots during the course of the experiments.