Established in 1872, the Herbarium of the Arnold Arboretum (A) contains approximately 1.5 million specimens housed in repositories across Harvard University. While the bulk of these collections reside on the main campus in Cambridge, Massachusetts, the Herbarium of Cultivated Plants (including spontaneous flora) and Seed Herbarium are curated at The Arnold Arboretum in Jamaica Plain, Massachusetts. Related campus-wide resources comprise the Harvard University Herbaria and are one of the largest (more than 5 million specimens) university collections in the world; third largest in the United States.
Dried specimens preserve genetic information, provide data on historical flowering and fruiting times, and play a vital role in understanding evolutionary relationships among plants, their geographic distributions, and their economic uses. Herbarium vouchers are routinely gathered to support research and are a necessary component of living collections documentation and worldwide plant expedition initiatives.