It contains a permanent collection of about 26,000 specimens of vascular plants, most of them from Illinois. Collections include important sets of A. Eads, R. M. Myers and R. T. Rexroat. Additionally, the fungi and a small collection of non-vascular plants and algae are housed in the Myers Herbarium. Important collections include those of A. L. Kibbe and E. L. Lambert.
All collections serve different purposes, including teaching, research, and public service.
MWI is being computerized to provide easier access to the herbarium information.