Article

Brassica olerocea L. belongs to the B. oleracea cytodeme with 2_n_ = 18. Biosystematic studi es show that the cylOdeme is composed of distinct species or groups of regionally distributed species. Wild populations of B. olerocea are distributed along the Atlantic coasts of Spain , France, and Great Britain , where they usually grow in steep parts of maritime c1iffs consisting of limestone or chalk. The size of the populations varies from one locality to another and a considerable intrapopulational vari ation is present in most of the populations regardless of size. Isozyme analysis indicates that even adjacent populations, geographically separated by a few kilometres only, may show quite different isozyme pattems. Thus, in most parts of the distribution area the species is represented by spalially well isolated populations and local adaptation has often given rise lo morphologically dislincl populations. The gene tlow between adjacenl populalions seems lO be smal.