"Pastel #20" has been determined to be a diploid using flow cytometry by
Dr. João Loureiro, Dr. Silvia Castro, José Cerca Oliveira, 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.
The Pastel series is documented to contain Rhododendron alabamense,
Rhododendron canescens, and Rhododendron flammeum.
Summary of Ploidy Levels
Diploid Rhododendron alabamense,
Diploid Rhododendron canescens,
Diploid Rhododendron flammeum,
Diploid "Pastel #6",
Diploid "Pastel #7",
Diploid "Pastel #20"
Source: Woodlanders Nursery
John and Sally Perkins