In the paper "Flow Cytometric Analysis of Ploidy in Rhododendron (subgenus Tsutsusi)", S. De Schepper1, L. Leus, M. Mertens, E. Van Bockstaele, and M. De Loose found 6 Rhododendron species of section Tsutsusi to be diploid.
In the paper "Ploidy Levels and Relative Genome Sizes of Diverse Species, Hybrids, and Cultivars of Rhododendron", Jeff R. Jones, Thomas G. Ranney, Nathan P. Lynch, and Stephen L. Krebs found 1 Rhododendron species of section Tsutsusi to be diploid. Results from this paper are denoted by j.
Triploids hybrid evergreen azaleas from these 2 papers are also listed here.
Diploid
Rhododendron indicum
Rhododendron kiusianum
Rhododendron mucronatum
Rhododendron noriakianum
Rhododendron scabrum
Rhododendron simsii
Rhododendron stenopetalum ‘Linearifolium’ j
Triploid
'Crimson Majesty' j
'Euratom'
'Euratom Orange'
'Red Wing'
Mixaploid
'Casablanca Tetra'
