Uromyces excavatus (de Candolle) Magnus, 1847
No host plant alternation. Spermogonia and aecia hypophyllous, uniformly dispersed all over the leaf. Uredinia missing. Telia hypophyllous, almost black, pustulate, sunken into the leaf tissue; spores one-celled; wall very finely verrucose, moreover in the upper half a sculpture of fine rods; apically a small, hyaline papilla. Infected plants are bushy, with short, broad, strongly thickened leaves.
Euphorbiaceae, narrowly monophagous
Euphorbia flavicoma subsp. costeana, verrucosa.
sometimes considered conspecific with U. tuberculatus.
the fungus has been found sometimes together with the aecia of U. verrucosae-craccae.
Brandenburger (1985a: 339), Buhr (1964b), Gäumann (1959a), González-Fragoso (1925a), Klenke & Scholler (2015a), Pellicier (2001a), Termorshuizen & Swertz (2011a).