Isoëtes butleri is an endangered lycopod (fern ally). In Illinois this species  has exhibited recent population declines, and managers are interested what factors influence population size.  This project is studying three ecological factors that may influence population size, PRS soil probes to determine differences in the soil nutrient levels, competition from the community may also influence population boundaries, and dead vegetation accumulation due to fire suppression.  For the genetic component we hope to conduct and investigation of population differentiation and inbreeding within the populations.  We have collected samples from 300 individuals, and will use microsatellite DNA markers to compare gene flow and inbreeding in Illinois populations. This small lycopod may be an important key to understanding wetland community and nutrient change as well as increase understanding of the ecology and genetics of rare and endangered species.