Diploïde populaties van de smeerwortel in Nederland bedreigd

S. officinale is a variable species. In the Netherlands three cytotypes occur: 2n = 24, 40, 48. The white-flowered diploid (2n = 24) is rare in Europe. The tetraploid cytotype (2n = 48) is represented by white- and purple-flowered plants in the Netherlands and by purple-flowered plants in Poland. In the Netherlands the diploids are very rare. In 8 localities, all occurring in the vicinity of the estate Oudegein (between the former villages Jutphaas en Vreeswijk, province of Utrecht) diploid plants were found. In two of these populations diploids and tetraploids grew intermingled. These mixed populations are now completely destroyed by reconstruction of roads and by town development, as are two populations of diploids. One diploid population is threatened and will probably disappear. The maintenance of the suitable habitat in the estate Oudegein is necessary for the preservation of the three remaining diploid populations of S. officinale in the Netherlands.