Polymorphism for cyanogenesis in Lotus corniculatus on links and machair in Orkney and the outer hebrides

Summary

A survey of the cyanogenic polymorphism in Lotus corniculatus L. at Birsay Links, Orkney, showed the relative frequency of the cyanogenic phenotype to be low (7–8 per cent) on the dry soils towards the centre of the links but to rise steadily towards the borders where soil moisture content was high. At other links and machair sites in Orkney and the Outer Hebrides the cyanogenic phenotype never fell below a relative frequency of 83 per cent although moisture content was usually no higher than that recorded for the driest soils at Birsay. Several possible explanations are presented for this difference.