On Grindelia lanceolata Nutt. (Rosin weed), a modification of the floral head; kataplasma, rosette type; a mass of overlapping involucral bracts (each external bract much thicker than normal ones), the whole assuming an ovoid shape, 2.4–3.5 cm. long; single chamber at center surrounded by much reduced bracts, elongate-ovoid; one or few galls on single plant, infrequent; Fayetteville, Ark.

leafy rosette gall...cecidomyiid

Galls are monothalamous, elongate-ovoid, and formed of overlapping bracts. Host: G. lanceolata. Distr.: Arkansas. Ref.: Wells (1921b)