Dr. James Cullen is Director of the Stanley Smith (U.K.) Horticultural Trust based in Cambridge. He served as Assistant Regius Keeper at RBG Edinburgh from 1972 to 1989, where he was responsible for research on Rhododendron classification based on both the dried and living collections. From 1976 to 2000 he was editor of The European Garden Flora (Cambridge University Press). He is the author of numerous scientific papers and contributions to flora, and holds an RHS Gold Veitch Memorial Medal.