Microbotryum flosculorum (de Candolle) Vánky, 1998
on Knautia, Succisa

Knautia arvensis, England, Vice County: Berks, VC22 © Malcolm Storey, BioImages

the anthers are filled with spores
spores

Succisa pratensis, Belgium, prov. Namur, Roly © Sébastien Carbonnelle

opened flowers
gall
the anthers are transformed into a purplish-brown powdery mass of spores. Spores 12-16 x 14-18 µm. The infection is systemic.
host plants
Caprifoliaceae, narrowly oligophagous
Knautia arvensis, dipsacifolia; Succisa pratensis.
synonyms
Bauhinus flosculorum (de Candolle) Denchev, 1997; Ustilago flosculorum (de Candolle) Fries, 1832.
references
Ainsworth & Sampson (1950a), Brandenburger (1985a: 600), Buhr (1964b), Klenke & Scholler (2015a), Kruse, Thiel, Frauenberger ao (2019a), Kruse, Thiel, Klenke, ao (2022a), Lutz & Vánky (2009a), Mayor (1967a, 1975a), Redfern & Shirley (2011a), Spooner & Legon (2006a), Vánky (1994a).