Fire, an important natural component of tallgrass prairie ecosystems, may be detrimental to the invasion and survival of many nongraminoid species. In the absence of fire, perennial forbs are reported to increase significantly in tallgrass prairie. Most studies involving fire and tallgrass prairie have concentrated on the dominant tallgrass species, but have failed to document the reproductive response of prairie forbs to fire. This study compares seed production of the common tallgrass prairie forb, Vernonia baldwinii Torr., among five native prairie sites which differ in time since the most recent burn