Status and distribution of Erythronium mesochoreum Knerr (Liliaceae) in Illinois
Thirteen populations of Erythronium mesochoreum Knerr, ranging from 15 to 3,940 individuals, were studied in nine northwestern and central Illinois counties. A species of tall-grass prairies and open oak woodlands throughout its midwestern range, it is present in open oak woodlands and forest-prairie borders characterized by acidic, silt loam soils in Illinois, where it was first reported in 1983. Many populations are threatened by mowing, woody invasion, railroad maintenance, or competition with exotic species, causing several colonies to be in danger of extirpation. Field investigations during the spring of 1998 resulted in the discovery of numerous additional populations on dry oak-hickory ridge tops in southwestern Macoupin County, suggesting the potential for other colonies near other known locations in Illinois.
McClain, W. E., J. E. Ebinger, and A. C. Koelling. "Status and distribution of Erythronium mesochoreum Knerr (Liliaceae) in Illinois." Castanea (1999): 346-349.