XVI International Botanical Congess

Fire during the growing season is a natural phenomenon in longleaf pine forests and Liatris species are common in the ground cover. L. gracilis (LG) and L. tenuifolia (LT) were two species studied in burn treatments ranging from January through August. Within each species, the height of flowering stalks was similar on all plots burned from January through July (mean height: LG = 53-67 cm, LT = 81-98 cm), however August fires produced much shorter stalks in both species (LG = 36-38 cm, LT = 53 cm). This substantial decrease in height may influence pollinator behavior. Interestingly, the proportion of each stalk that supported flowers was the same across all treatments for LG and greater in August burns for LT. These results indicate that fire in early versus late growing season may affect different components of flower production in different ways.