Nipplewort Rust

Nipplewort Rust

Observation - Nipplewort Rust - UK and Ireland. Description: Raised red blisters up to about 8 mm across, raised about 1mm at centre, on undersides of Nipplewort leaves and smaller ones on a few stems. Also visible as flatter red patches on tops of leaves. The blisters are covered with tiny cup-like structures up t

Raised red blisters up to about 8 mm across, raised about 1mm at centre, on undersides of Nipplewort leaves and smaller ones on a few stems. Also visible as flatter red patches on tops of leaves. The blisters are covered with tiny cup-like structures up to about 400 microns across, with flattish yellow floors and white raised circular walls. The whole structure of blister and cups has a granular structure under microscope, like different coloured sands. The spores found from chopping up some of the blister were subglobular. The majority were speckled and measured 18-23 x 16-20 microns, with a few bronze-looking 19-25 x 15-21 microns, globose - ovoid. I also found some spores shaped like flattened globes, which measured 19-29 x 17-25 microns, stuck together in small groups.