Rhododendron 'Van', which is van Veen introduced by Paul Greibnoween and Harold Greer and documented as R. griersonianum x 'Countess of Derby', has been determined to be a triploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca, and Mariana Castro
Plant Ecology and Evolution Group,
Centre for Functional Ecology,
Department of Life Sciences,
Faculty of Science and Technology,
University of Coimbra, Portugal.
In the case of triploid 'Van', a suspected diploid crossed with a tetraploid produced a triploid indicating that normal reduced meiosis most likely occurred for both parents. In other words, 'Van' having 39 chromosomes received 13 chromosomes from the suspected diploid R. griersonianum and 26 chromosomes from the tetraploid 'Countess of Derby'.
Summary of Ploidy Levels
Triploid 'Anna Rose Whitney',
Triploid 'Lucky Strike',
Triploid 'Van',
Tetraploid 'Countess of Derby'
Source: Greer Gardens
John and Sally Perkins
