Alnus incana, Belgium, prov. Antwerp, Mol, Klein Verkallen © Carina Van Steenwinkel

same leaf, underside

detail with clestothecia

on top of the cleistothecia the gelatinous cushion is visible that is formed by the penicillate cells

cleistothecium with two-spored asci

penicillate cells

gall

mycelium hypophyllous, weak, effuse (also internal). Conidia single, clavate, without fibrosin bodies, on a long conidiophore. Cleistothecia with 15-30 asci, with two spores. Appendages 6-15, equatorial, 1-2.5 the diameter; they are acicular, stiff, with a bulbous swelling at their base.

host plants

Betulaceae, monophagous

Alnus cordata, glutinosa, incana & subsp. rugosa, x pubescens, viridis.

references

Braun & Cook (2012a), Bresinsky (2016a), Klenke & Scholler (2015a), Leysen (2017a).