Alnus glutinosa, Naardermeer

Alnus glutinosa, Leiden

Alnus glutinosa, Nieuwendam; upper side of the leaf

underside

asci, strong magnification (lighted from below)

Alnus glutinosa, Belgium, prov. Antwerp, Tongerlo, Engelse Kamp © Carina Van Steenwinkel

detail; the mealy appearance of the galls indicates that the fungus is sporulating

ascus, filled with spores (congo red staining)

gall

the galled spots rarely exceed 1 cm. Never witches’ brooms.

host plants

Betulaceae, monophagous

Alnus ?cordata, glutinosa, glutinosa x incana, incana subsp. rugosa.

notes

the gall can be mistaken for the one caused by Acalitus brevitarsus.

references

Bacigálová, Lopandic, Rodrigues ao (2003a), Bacigálová, Mułenko& Wołczańska (2005a), Bataille (1936a), Buhr (1964b), Dauphin & Aniotsbehere (1997a), Dietrich (2016b), Jage, Kruse, Kummer ao (2013a), Klenke & Scholler (2015a), Kozłowska, Mułenko & Heluta (2015a), Kruse (2014a, 2019a), Redfern & Shirley (2011a), Roskam (2009a), Tomasi (2014a).