The Herbarium

The Herbarium at the University of California, Riverside (UCR) serves as an important source of information for the Southern California regional community of academic researchers, private biological consulting firms, farmers and other individuals involved with plants as a business, research topic, management concern, or just a personal interest as well as for botanists from around the world. One hundred percent of its specimens are databased and 87%, georeferenced (mappable in GIS). Currently UCR is the 4th largest contributor to the Consortium of California Herbaria (some 142,736 specimens). UCR's oldest specimen was taken September 1859 on the Hayden Expedition, Powder River, Wyoming. The UCR Herbarium has documented the abundance and distribution of species, their changes in range over time (such as new records in Los Angeles County of species known elsewhere), the arrival of invasive species, rediscovery of "extinct" species, and the collapse of Bromus trinii/berteroanus.

The UCR herbarium currently (January, 2014) houses over 222,017 vascular specimens. Of these, ca. 181,533 specimens are from the United States, of which ca. 147,635 are from California. Mexico is represented by ca. 36,490 specimens. The rest of the specimens is mainly miscellaneous collections from other areas of the Western Hemisphere. It is a general collection, but with particularly strong holdings of Juniperus, Triticeae (B. L. Johnson & J. G. Waines collections of Triticum and Aegilops, plus allied genera), and Phaseolus. The herbarium is one of the strongest for the flora of Southern California and is also very strong in the flora of western Mexico. A detailed overview of the collection is available on our summary web page.

The lichen collection currently (January, 2014) contains 15,290 specimens, 12,932 of which are from California. The major part of the collection is the work of two collectors: F.M. Reed from the early 20th century and Kerry Knudsen who is currently collecting in California and the Czech Republic. Other important collectors represented in the herbarium include H. E. Hasse, Jana Kocourková, James C. Lendemer, T.H. Nash and Rick Riefner, Jr. The collection also specializes in Acarosporaceae and in lichenicolous fungi.

UCR houses a collection of unusually high quality specimens, there are few scrappy specimens or specimens with scant label data. About half of our specimens have latitude/longitude data. Many of our collections were generated locally in relatively recent times and so provide one of the best current pictures of the flora of southern California. Our collection from western Mexico is also unusually strong and in many cases is not duplicated elsewhere.

The UCR Herbarium is heavily used by the general community in southern California. Most visitors are people who bring in plants for identification. Also important are the volunteers who contribute their time and brains to the operations of the herbarium. Others are researchers coming mostly from southern California, but also Canada and other parts of the world to study the collection.

The UCR herbarium is one of the most active in California in making identifications for the public and for other researchers. Every year we make 5-10 thousand identifications for individuals not affiliated with the herbarium, ca. 1/4 of these are made into specimens. In addition we have an active collection program which generates thousands of additional specimens every year. As a result of the massive flux of material resulting from these two sources we are one on the more active herbaria in exchange. We send out many thousands of specimens to ca. 25 other herbaria. In many cases we are among the other herbaria's most active exchange partners and, even in the case of some very large herbaria (e.g., RSA), we are in many years their major exchange partner in terms of numbers of specimens sent to them. The UCR Herbarium also actively helps researchers unable to come to Riverside to look at specimens in the inventory by loaning them specimens through their local herbarium. Loans averaged 10 to 15 per year.


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