The herbarium of the Botanical Institute of Barcelona known internationally under the acronym BC, specialises in western Mediterranean flora. It also contains plants from Europe, South America, Africa and the other continents. Herbaria are biological collections that hold a scientifically classified and systematically arranged representation of the diversity of plants to be found on Earth. Our knowledge about the plant world is based, ultimately, on these collections. Herbaria are also the natural destination of the information gained from plants used in scientific research, from systematic, molecular and karyological research work, etc., to plant biodiversity inventory studies, as it is always necessary to preserve specimens that will allow the subsequent identification of samples used. The ensemble of herbaria at the Botanical Institute of Barcelona is the largest collection of plants in Catalonia. These collections served as a reference for Flora dels Països Catalans (Flora of the Catalan Territories), a work by Oriol de Bolòs and Josep Vigo, and for the Flora Ibérica (Iberian Flora) project and the leading botanical works published on the flora of the Iberian peninsula and western Mediterranean. It is an open collection that is constantly incorporating new scientific reference material on our flora. The collections at the Botanical Institute comprise some seven hundred and fifty thousand herbarium specimen sheets grouped into three sections: historical herbaria, with specimens collected between the 17th and 19th centuries; the general herbarium, consisting of collections assembled between the 19th century and the present day, and the cryptogam herbarium. Collection fund The collections at the Institut Botànic comprise more than eight hundred thousand herbarium specimen sheets grouped into four sections: the historical herbaria with specimens collected between the 17th and 19th centuries, the general herbarium, which includes collections assdembled between the 19th century; the “other herbaria” (separated by their characteristics) and the herbarium of cryptogam herbarium.