Knopper gall

Oak sudden death Phytophthora ramorum fungi and algae pest on Oak tree Quercus

Oak spangle galls from wasp Tilia platyphyllos and Silk button galls from wasp Neuroterus numismalis on Oak leaf Quercus robu

Oak Quercus robur sketchbook page including flowers and young leaves

Knopper gall Andricus quercuscalicis on English Pendunculate or Common Oak Quercus robur.   Illustrations shows  mature gall, formed from acorn embryonic tissue thanks to the gall wasp

Knopper gall Andricus quercuscalicis and Oak apple gall Cynips quercusfollii on English Pendunculate or Common Oak Quercus robur