Spermogonia epiphyllous, in groups, honey-coloured.
Aecia hypophyllous, in groups, cupulate, with a short white recurved peridium, the peridial cells rhombic, inner wall 3-4 µm thick, outer wall 8-10 µm thick, striate. Aeciospores 16-23 µm diam., globose to ellipsoidal, orange-yellow, the wall ca 1 µm thick, finely verrucose.
Uredinia amphigenous, minute, cinnamon-brown, roundish, on the stems linear and often confluent. Urediniospores 22-30 x 17-23 µm, the wall 1.5-2 µm thick, minutely spiny, with two equatorial pores.
Telia amphigenous, oblong or roundish in outline, compact, chocolate brown to black. Teliospores 30-56 x 14-24 µm, ellipsoidal to clavate, the apex rounded to conical and often darker, slightly constricted at the septum, tapering below; the wall brown, smooth, the pore in the upper cell apical to slightly offset, in the lower cell near the dividing wall. Pedicel about the same length as the spore.
Description adapted from Wilson & Henderson (1966).
Not formally assessed; considered as of Least Concern in Wales.
On living leaves and stems of Galium species, especially C. palustre.