Rhododendron 'Grace Seabrook', which is a Cecil Seabrook hybrid documented as 'The Honorable Jean Marie de Montague' x R. strigillosum, 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.
Rhododendron 'Taurus', which is also documented as 'The Honorable Jean Marie de Montague' x R. strigillosum, has been determined to be a triploid using flow cytometry by Dr. Thomas Ranney, J.R. Jones, and Nathan Lynch. 'Taurus', although reluctant to be a parent, appears to be both seed and pollen fertile.
Rhododendron 'The Honorable Jean Marie de Montague', although a diploid, is documented as the parent of several triploids indicating 'The Honorable Jean Marie de Montague' may throw more unreduced gametes than most diploids.
Summary of Ploidy Levels
Diploid 'The Honorable Jean Marie de Montague',
Triploid 'Grace Seabrook',
Triploid 'Taurus'
Source: Werner Brack
John and Sally Perkins
