We undertook floristic studies of 104 grasslands in the tallgrass prairie region of Kansas to examine differences in the floristic quality of five common grassland management systems. The different grasslands were warm-season prairie hay meadows, warm-season native pastures, cool-season planted hay fields, cool-season planted pastures, and Conservation Reserve Program (CRP) fields. We recorded 383 vascular plant taxa of which 79% were native and 21% were non-native. Species richness at our sites ranged from seven for a cool season pasture to 109 for a warm-season hay meadow. Our results show that warm-season hay meadows exhibit highest species richness (256 taxa) and are habitats for highly conservative native taxa, while degraded grasslands have a higher number of alien taxa (29% in cool season planted hay fields) and lower species richness (136 for cool season hay fields). We computed Floristic Quality Assessment Index (FQI) values, which ranged from 0.3 for a cool-season pasture to 41 for warm-season prairie hay meadows while modified FQI ranged from 0.09 for a cool-season pasture to 4.48 for a warm-season prairie hay meadow. FQI values across management types differed significantly from each other (p=0.000). We conclude that native prairie hay meadows are significant reservoirs of conservative grassland species. In addition, the FQI can be a useful tool for discerning effects of land management on grassland vegetation.