The R. L. McGregor Herbarium houses approximately 400,000 specimens. The majority of these comprise exsiccatae, seed, boxed, and fluid-preserved vascular plant specimens. The herbarium also houses smaller holdings of bryophytes and fungi, and a growing lichen collection. Sixty-five percent of the collection represents the flora of the grassland biome of central North America. The herbarium also contains a library of 1,400 books and 14,000 scientific articles, and a collection of more than 50,000 photographic slides and digital images. Search the collection.

For those interested in using the collections, the herbarium has a detailed collection management policy addressing acquisitions, deaccessions, loans, destructive sampling, data use, pest management, and disaster preparedness and recovery.

The herbarium’s formal name is the R. L. McGregor Herbarium; the index Herbariorum Acronym is KANU.