A glossy, hairless, green-shading-to-red gall on the lower side of the lamina of leaves of Quercus imbricaria. The gall projects in a cylindrical, hemispherical, or near-globular form, and it is thick-walled, but only a small part of the bottom edge of the projection; the majority of the space is a hollow formed by the deformation of the leaf. The surface is often subtly striped with either dark and light shades of green or green and red. This gall was initially taken to be Amphibolips quercusrugosa, which is listed on this host by Weld and is described has having a similar "sunken, concave" area on the upper side. However, that gall is much wider and does not project below the leaf to the extent that this gall does. Galls consistent with quercusrugosa have been found in Florida and potentially as far north as North Carolina, while the "nipple gall" has been found near Washington DC, Ohio, and Missouri.

- Gallformers Contributors: (2023) Gallformers ID Notes^©