Puccinia lapsanae

Puccinia lapsanae affects Nipplewort (Lapsana communis), causing galls in the aecial stage, often seen on the rosette-leaves early in spring. Leaf blades, veins and petioles have conspicuous reddish bulges with pale yellow aecia, on both sides of the leaf.  Small chestnut-coloured uredinia and dark brown telia are present later, but are not gall causing.

Lapsana communis is listed on the 'Plant Parasites of Europe' website as being the alternate (aecial) host for Puccinia opizii; a Carex being the primary host bearing the uredinia and telia.  There are a few records for Britain.  It is not in Redfern & Shirley as a gall-causer but is in *Roskam, where the galls are stated to cause 'only minor hypertrophies' - i.e. swellings or bulges.   They are described as protruding on the underside and concave on the uppersides, on leaf blades only, with more or less deep yellow aecia.  The presence of uredinia and telia on Nipplewort would rule out the possibility of Puccinia opizii, but galls and aecia should be carefully examined.

*Roskam, J.C. & Carbonelle, S. 2023. Plant Galls of the Netherlands, Belgium and Luxembourg.  KNNV Publishing 

host/gall

Photograph the rust and the gall on the host, photographing both sides of the leaf and the petioles.  Ensure you have noted the host-plant species in your comments

Nipplewort Lapsana communis