The agamous generation of the knopper gall, Andricus quercuscalicis
gall, early August (photo Hans Jonkman)
same gall, pulled out of the cupula
the “stalk” of the gall has pushed itself between cupula and acorn
The gall is attached to the cupula, next to the attachment of the acorn
The gall chamber, still quite small, is located in the “stalk”
Another specimen, autumn aspect; the gall chamber has grown proportionally
The acorn has been overgrown and is aborted.