Rhododendron decorum ssp. diaprepes 'Gargantua', which is often documented as a triploid, has been determined to be a tetraploid 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 decorum ssp. diaprepes 'Gargantua' is known to be self fertile.
All elepidote Rhododendron species are documented to be diploids. Whether 'Gargantua' represents the sole anomaly from this rule is not known at this.
Summary of Ploidy Levels
Tetraploid Rhododendron decorum ssp. diaprepes 'Gargantua'
Source: Whitney Nursery
Source: Jim Barlup
John and Sally Perkins
