Rhamnus lanceolata Pursh (Lance-leaved Buckthorn, Rhamnaceae), Its Distribution and Abundance in Illinois

During the present study we searched for populations of Rhamnus lanceolata Pursh (lance-leaved buckthorn) throughout its known range in Illinois. Considered a relatively common species based on herbarium records, the authors, with a combined total of more than 112 years of field work in Illinois, have rarely encountered this species. During part of a larger study involving 80 native Illinois species, we searched for all of these species in most herbaria in Illinois, and a few outside the state, to determine potential population sites. More than 240 specimens of R. lanceolata were found representing 103 populations. Of the 103 populations identified from the herbarium search, we relocated 13 populations from eight Illinois counties. We are not sure of the normal habitat for lance-leaved buckthorn in Illinois, but it is probably a species of hill prairies, hill prairie/forest interface, associated limestone glades of hill prairies, ravines and brushy areas of savannas, and in northeastern Illinois, calcareous fens.