Spermogonia epiphyllous, few, flat, reddish-yellow, inconspicuous. Spermatia 6µm long.
Aecia uredinoid, amphigenous, usually on the veins and petioles where they cause distortion, large, irregularly extended, without paraphyses, slightly pulveulent, orange-yellow. Aeciospores 25-28 x 18-21 µm, ellipsoidal to obovoid, contents orange, wall 2-3 µm thick, hyaline, echinulate grading to smooth at the base.
Uredinia hypophyllous, small, round, scattered, lemon-yellow, very pulverulent, with peripheral paraphyses. Uredospores 20-30 x 18-25 µm, globose to obovoid, wall 1-1.5µm thick, pale yellow, sharply echinulate above, less so below, pores obscure.
Telia hypophyllous, small, round, naked, pulverulent, brownish-black. Teliospores 35-49 µm diam., usually 3-celled, subglobose or ± triangular, flattened, with one basal and two apical cells, chestnut brown, scarcely constricted, with obtuse warts especially about the pores, wall uniformly 1.5-2.5µm thick with one apical pore in each cell. Pedicels hyaline, one to one and a half the length of the spore, deciduous.
Not formally assessed for GB as a whole, but considered as of Least Concern for Wales by Woods et al. (2015).
On living leaves and stems of Filipendula ulmaria.
Throughout the British Isles and Ireland.