The Morton Arboretum’s Herbarium houses more than 187,000 vascular plant specimens, 17,000 lichens, and 1,300 bryophytes, many from Illinois and Missouri.
It is the third-largest arboretum herbarium in North America. Its primary emphasis is on woody plants, both cultivated and spontaneous. It is a major resource to researchers in botany, genetics, conservation ecology, restoration, and other disciplines.
Plants of the Chicago region
One of the herbarium’s important collections vouchers the flora of the Chicago region. The region consists of 24 counties, five in Wisconsin, seven in Indiana, one in Michigan, and 11 in Illinois.
More than 2,500 taxa are recorded from this area and have representatives in the herbarium from each of the counties in which they occur. This herbarium collection is the database for Swink and Wilhelm’s Plants of the Chicago Region (4th edition, 1994). The Arboretum has the most complete collection of dried plants for this rich and diverse flora, which are included in vPlants, a virtual herbarium of Chicago-region plants.