on evolutionary relationships. Their work was more supportive of Sleumer's original system than the later modifications introduced by Chamberlain et al.. The major finding of Goetsch and colleagues was that all species examined (except R. camtschaticum, subgenus Therorhodion) formed three major clades which they labelled A, B and C, with the subgenera Rhododendron and Hymenanthes nested within clades A and B as monophyletic groups respectively. By contrast subgenera Azaleastrum and Pentanthera were polyphyletic, while R. camtschaticum appeared as a sister to all other rhododendrons. The small polyphyletic subgenera Pentanthera and Azaleastrum were divided between two clades. The four sections of Pentanthera between clades B and C, with two each, while Azaleastrum had one section in each of A and C. Thus subgenera Azaleastrum and Pentanthera needed to be disassembled, and Rhododendron, Hymenanthes and Tsutsusi correspondingly expanded. In addition to the two separate genera included under Rhododendron by Chamberlain (Ledum, Tsusiophyllum), Goetsch et al.. added Menziesia (Clade C). Despite a degree of paraphyly, the subgenus Rhododendron was otherwise untouched with regard to its three sections but four other subgenera were eliminated and one new subgenus created, leaving a total of five subgenera in all, from eight in Chamberlain's scheme. The discontinued subgenera are Pentanthera, Tsutsusi, Candidastrum and Mumeazalea, while a new subgenus was created by elevating subgenus Azaleastrum section Choniastrum to subgenus rank. Subgenus Pentanthera (deciduous azaleas) with its four sections was dismembered by eliminating two sections and redistributing the other two between the existing subgenera in clades B (Hymenanthes) and C (Azaleastrum), although the name was retained in section Pentanthera (14 species) which was moved to subgenus Hymenanthes. Of the remaining three sections, monotypic Viscidula was discontinued by moving Rhododendron nipponicum to Tsutsusi (C), while Rhodora (2 species) was itself polyphyletic and was broken up by moving Rhododendron canadense to section Pentanthera (B) and Rhododendron vaseyi to section Sciadorhodion, which then became a new section of subgenus Azaleastrum (C). Subgenus Tsutsusi (C) was reduced to section status retaining the name, and included in subgenus Azaleastrum. Of the three minor subgenera, all in C, two were discontinued. The single species of monotypic subgenus Candidastrum (Rhododendron albiflorum) was moved to subgenus Azaleastrum, section Sciadorhodion. Similarly the single species in monotypic subgenus Mumeazalea (Rhododendron semibarbatum) was placed in the new section Tsutsusi, subgenus Azaleastrum. Genus Menziesa (9 species) was also added to section Sciadorhodion. The remaining small subgenus Therorhodion with its two species