GOODWIN1, reviewing the distribution of carotenoids in non-photosynthetic tissue, came to the conclusion that it was very difficult to see their taxonomic significance. Rubixanthin seemed to be restricted to Rosa spp.2 and it was suggested that, if a carotenoid mixture contained significant amounts of rubixanthin, then one could say with some confidence that the source of rubixanthin was the hips of a species of Rosa1. Rubixanthin, however, has been identified in several other plants, namely, Cuscuta salina, C. subinclusa3 and Gazania rigens4. Valadon5 has also identified this pigment in the orange peel fungus, Peziza (Aleuria) aurantia, but Jensen6 failed to confirm this result and had found a new pigment. With a view to finding whether rubixanthin was restricted to some members of the higher plants, we have reinvestigated the carotenoid composition of the orange peel fungus.