Rust on dock (Rumex)

I’ve seen the spots on lots of dock leaves and finally found some with aecidia

Not good on docks, didn’t know there were so many, assuming its R. obtusifolius. Spores from aecidia are quite irregular.

Henderson “Rusts by host plant” has Uromyces rumicis as likely contender for R. obtusifolius, could it be anything else?

Hi Adam

if you look again Henderson’s “Rusts by host plant” you’ll see that Uromyces rumicis only has stages II & III on Rumex and as you point out these sori are aecial. This is Puccinia phragmitis, which alternates with Phragmites – might there have been reeds nearby? It doesn’t look like R. obtusifolius but it’s not easy identifying docks from a portion of a leaf (and they can hybridise – fruits are often necessary to be 100% certain); in any case the exact identity of the host is irrelevant – it isn’t a sorrel and so must be Puccinia phragmitis.

best wishes

Chris