Rough, uneven swelling, usually near base of stem...Lasioptera asterspinosae White
Galls may completely or only partially encircle the stem. They are brown, polythalamous, and spongy. Galls occur from ground level to 1 m above the ground. Larvae overwinter in the galls, and adults emerge in spring. Host: A. spinosus.
”- Raymond J. Gagne: (1989) The plant-feeding gall midges of North America©