- A hard spherical gall which forms on the common oak in response to the developing larva of a gall wasp.
More example sentences
- The wasp is Andricus kollari, family Cynipidae
- The oak marble gall is frequently confused with the oak apple gall, caused by another gall wasp, Biorhiza pallida.
- The marble gall, a green or brown growth about 2.5 cm (1 inch) in diameter, is caused by Andricus kollari.