The United States National Herbarium is a collection of five million preserved plant specimens housed in the Department of Botany at the National Museum of Natural History, which is part of the Smithsonian Institution. It represents about 8% of the plant collection resources of the United States and is one of the ten largest herbaria in the world.[1]
The herbarium was founded in 1848, when the first collections were accessioned from the United States Exploring Expedition, when botanists pressed approximately 50,000 specimens, representing 10,000 species of plants.[2] The Index Herbariorum code assigned to this herbarium is US[3] and this abbreviation is used when citing housed specimens.