Spermogonia pale yellow, roundish.
Aecia on the leaves and petioles, on the leaves scattered or circinate, on the petioles and nerves in dense elongate clusters causing a slight hypertrophy, yellowish, pustulate, with a poorly developed peridium; aeciospores 18-35 x 16-26 µm, verruculose, orange.
Uredinia hypophyllous, scattered, minute, roundish, pulverulent, cinnamon; urediniospores 20--30 x 18-25 µm, globose to obovoid, pale brownish-yellow, the wall echinulate, with 3 usually equatorial pores.
Telia similar, but dark brown, on the petioles more elongate; teliospores 24-36 x 16-25 µm, ovoid to cylindrical, rounded at both ends or gradually attenuate below, slightly constricted at the septum, yellowish-brown or brown, wall reticulate, not thickened apically, pore of upper cell apical, of lower subequatorial, pedicel hyaline, thin, as long as the spore.
On living leaves of Anthriscus sylvestris and Myrrhis odorata, possibly also on Chaerophyllum temulum.
Throughout Great Britain and Ireland.