A herbarium is a collection of preserved plant specimens. These specimens may be whole plants or plant parts. These will usually be in a dried form mounted on a sheet but depending upon the material, may also be kept in alcohol or other preservative. The specimens are stored with a data label. The label describes useful information including the plants's Latin name, the origin of the collection, the date of collection and the name of the collector.
Herbariums are essential for the study of plant taxonomy, the study of geographic distributions and the stablizing of nomenclature. Specimens housed in herbaria may be used to identify the flora of an era. Herbaria also preserve a historical record of change in vegetation over time. Environmental scientists make use of such data to track changes in climate and human impact. Herbaria may also be a repository of viable seeds for rare species.