Puccinia cladii  

Uredinia on both surfaces of leaf, scattered or grouped, confluent, elongate, to 8 mm long, surrounded by the ruptured epidermis, dark cinnamon-brown. Urediniospores (27-) 35-42 x (20-) 26-32 µm, broadly ellipsoidal to obovoid, cinnamon-brown, wall 2-2·5 µm thick, very finely and often remotely echinulate with spines scattered over the surface, with 3 (rarely 4) ± equatorial pores, the pedicel hyaline and usually dehiscent.
Telia similar in external form to the uredinia, blackish-brown. Teliospores 42-51 x 18-26 µm, ellipsoidal to clavate, the apex rounded to obtuse, usually narrowed below, somewhat constricted at the ± median septum, dark chestnut-brown, paler below, wall 1-2 µm thick at the sides, greatly thickened (to ca 9µm) in the apical part, smooth, the pedicel brownish, to one-third the length of the spore, persistent.

Map of known distribution in Great Britain and Ireland.