A spongy spherical gall which forms on oak trees in response to the developing larvae of a gall wasp.
- The wasp is Biorhiza pallida (in Europe) or Amphibolips confluenta (in America), family Cynipidae
More example sentences
- Oak apple galls are sometimes mistaken for an actual crop of the tree, such as apples on on apple tree, but are actually deformed leaves.
- An oak apple is also known as an oak gall.
- The so-called oak apple, a round, spongy, fruitlike object about 2.5 to 5 cm (1 to 2 inches) in diameter, is caused by the larvae of the gall wasp Biorhiza pallida.
More definitions of oak appleDefinition of oak apple in:
- The US English dictionary