Oecologie en verspreiding van Vaccinium x intermedium Ruthe in Nederland

Vaccinium X intermedium Ruthe is a natural hybrid of V. myrtillus and V. vitis-idaea. The hybrid shows conspicuous intermediacy between both parent species. In Great Britain the hybrid could only be resynthesized when V. myrtillus was the female parent. The plant shows partial sterility and a greater capacity to reproduce vegetatively than both parent species. The existence of two forms of V. X intermedium is discussed. Most probably nm. multiflorum is the backcross of nm. intermedium and V. vitis-idaea. Of all localities in the Netherlands the Imbosch (National Park Veluwezoom) has been thoroughly investigated. In the Imbosch-area the percentage of localities situated in heath communities and open pine forests (84%) exceeds the percentage in the whole country (53%). This is probably the result of the relatively high rainfall in the Imbosch, causing a humidity comparable with that in forests. In the Netherlands as well as in Great Britain the occurrence of V. X intermedium seems to be correlated with disturbed habitats. It has been pointed out that the number of localities of V. X intermedium has increased in the last decade.