Filipendula spp. are attacked by rust fungi on the genusTriphragmium. Several related genera (tribe Phragmidieae) occur wholly or partly on Rosaceae, and all are restricted to genera in Rosoideae. It appears, by inference, thatFilipendula also belongs to this subfamily. The only recorded rusts of Spiraeoideae are distantly related, and appear, from morphology and total host relationship, to be of much earlier origin.