Large, woolly stem gall [on A. polycarpa] not covered with small leaf clusters...Asphondylia floccosa Gagné
Masses of galls are 0.5–1.5 cm in diameter on apices of plants in the summer and are 1–10 cm in diameter and farther down on the plant in winter. They are monothalamous or polythalamous, white, sometimes pink basally...
- Raymond J. Gagne: (1989) The plant-feeding gall midges of North America©