INTRASPECIFIC BIODIVERSITY IN MEADOWS .1.A CASE-STUDY OF LOCAL VARIATIONS OF THE CYANOGENIC POLYMORPHISM IN LOTUS-CORNICULATUS L. (FABACEAE)

Cyanogenic polymorphism of Lotus corniculatus L. plants growing on a c halky lawn and a meadow were compared: the two sites are quite close ( 200 m). Lotus from the lawn are highly polymorphic (73 % of the plants are not cyanogenic [Acli], [acLi], [acli]), while in the meadow nearl y all are cyanogenic (94 %). Lotus plants escape herbivory by spatial and temporal avoidance. Severe constraints due to poor soil nutriments of the lawn account for the polymorphism observed at that site. In th e meadow, competition will select for fast-growing individuals. The re lationship with fitness for cyanogenesis is discussed.