Reproductive effort in two cultivated leek species was determined under the same conditions. Reproductive effort was estimated as the percentage energy content in sexual organs and the organs of clonal growth out of the total energy content of vegetative and reproductive tissues at the end of the plant's life. One of the plants was essentially a sexually reproducing cultivar. The other, an Allium belonging to the porrum group, had not been selected for agronomic purposes. Though more diverse in its reproductive mode, this plant spreads essentially via underground vegetative means. Its development in the centre of France still reflects the morphological growth responses to the selective pressures of its original circummediterranean habitat. The portion of reproductive effort contributed by sexual organs in the two leek species was not significantly different, 31% in the cultivar and 35% in the nonselected plants. Total reproductive effort was much higher for the nonselected plants (55%) than that for the cultivar (33%), with the energy allocation to offset bulb production (20%) in the nonselected plants. The reproductive effort of the biennial cultivar approximates that found for numerous annual species. Despite the very high mortality of cultivar seedlings and cultivar inflorescences the small number of offset bulbs produced by the nonselected plant did not ensure as rapid a propagation as observed for the cultivar.