An investigation into the effect of different environments on lucerne varieties seeded in southern latitudes was carried out at Cambridge on spaced‐plants and on yield trials during 1954–60. The varieties Flandria (northern French), Provence (southern French), and Grimm (Canadian) were multiplied in Cyprus for two generations under the control of the Department of Agriculture there. The English variety Eynsford was multiplied in countries of the Mediterranean area for one generation under the supervision of the O.E.E.C. and F.A.O.Morphological and physiological changes took place in Flandria. Eynsford and Grimm, the significance of which in relation to the generation, the authenticity of variety and the yield of fodder are discus