Cirsium dissectum, England, Oxon, VC23 © Malcolm Storey, Bioimages

gall

one or more cavities in the disfigured, never opening flower head are filled with a brown, granular-powdery mass of spore balls. Sometimes similar sori are formed as pustules on the peduncle below the flower head. The easily disintegrating spore balls consist of c. 2-5 spores.

host plants

Asteraceae, narrowly oligophagous

Cirsium dissectum, helenioides, heterophyllum; Saussurea alpina.

Experimentally also C. oleraceum, palustre, and vulgare could be infected.

references

Ainsworth & Sampson (1950a), Brandenburger (1985a: 666), Buhr (1964b), Dietrich (2013a), Klenke (2002a), Klenke & Scholler (2015a), Tomasi (2014a), Vánky (1994a).