Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Oak marble galls develop as a chemically induced distortion of leaf buds on pedunculate oak Quercus robur, or sessile oak trees, caused by the parthenogeneticgall wasp Andricus kollari, Hartig, 1843 which lays eggs within leaf buds using their ovipositor. The Turkey oak Quercus cerris, introduced into Britain in 1735, is required for the completion of the life cycle of the gall. The oak marble gall is frequently confused with the oak apple gall, caused by another gall wasp, Biorhiza pallida. Oak marble galls are also known as the Bullet gall, Oak nut or Devonshire gallSynonyms for the species are Cynips kollari, Andricus quercusgemmae, A. hispanicus, A. minor, A. indigenus and A. circulans. The gall growth first appears as a rounded mass of green plant tissue on the leaf buds of the oak, later becoming hard and brown, being up to approximately 25 mm / 1 in in diameter. Although nearly spherical, the galls often have a number of little flattened nodules.