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PPD Botany lab

Plant Pest Diagnostics Center - Botany Laboratory

History of the CDFA Botany Lab

Botany lab staff work to identify, study, catalogue and assess the weed risk of California's rich and ever-expanding floral diversity. An interesting historical perspective is given (then as a current perspective) by Herbert F. Copeland (1935, Madroño 3: 42-50)

In 1911 a cooperative USDA/State seed lab was founded in Berkeley. It moved to Sacramento in 1921, at which time the Herbarium (CDA) and Seed Laboratory were established. The Seed Herbarium was then separated from the main Herbarium, forming a second, very significant collection. The total number of specimens in the plant Herbarium as of late 2007 is about 50,000. The Herbarium also maintains an extensive botanical library consisting of about 1500 volumes, and a searchable database of over 12,000 botanical and weed science articles available on the shelf or as reprints. In 1992 the Botany Lab and it's Herbarium moved to its current Meadowview Road facility, along with the rest of the Plant Pest Diagnostic Branch.

Botanists began with Margaret K. Bellue, who at that time identified both weeds and seeds. She was one of the co-authors for the original Robbins "Weeds of California" in 1941. Dr. Thomas C. Fuller followed in the late 1950s and retired in 1982. His book, "Poisonous Plants of California," published in collaboration with Elizabeth McClintock of the California Academy of Sciences, remains a significant reference work. Dr. G. Douglas Barbe worked with and trained under Tom Fuller for seven years, then was the sole botanist until his own retirement in 1996. Dr. G. Fred Hrusa, the most recent Senior Plant Systematist, arrived in 1997 and retired in 2017, and Dr. Dean Kelch was briefly employed as a Plant Systematist from 2006-2011. The current Senior Plant Taxonomist is Dr. Genevieve Walden, who arrived in 2017.
The Botany Lab was initially intended as a means of identifying current and potential weeds of agriculture. Its primary mission remains the identification of submitted specimens and first line assessment of their potential invasiveness. However, this role has expanded over the years as scientific understanding of the effects of invasive species on rangelands and native ecosystems has increased. Identifying and interpreting the behavior of agricultural weeds remains an important part of the Botany Lab's function, but identification of host plants for pathogens, insects and nematodes is a more recent emphasis, requiring an additional emphasis on horticultural and agricultural taxa. In addition, wildland weeds, and even native species at risk are also evaluated as needed. The botany lab consults extensively  with state agricultural officers and extension agents and the USDA, as well as non-governmental organizations such as the California Invasive Plants Council (Cal-IPC), the California native Plant Society (CNPS) to identify the most threatening plant invaders. Collaborations occur with California Department of Fish and Game (DFG) and the Fish and Wildlife Service (USFWS) to assess the status and threats to native plant species.To all these ends Botany lab scientists collaborate with botanists around the world - they provide information and specimens as to identity, distribution, and behavior in the plants native or introduced habitats outside of California.

The Botany Lab is a participant in a long term project to database the entire collection and make the data available on the Web as part of the Consortium of California Herbaria, which provides plant specimen data from (currently) 18 different California herbaria. One-stop shopping for botanical information will revolutionize our ability to understand plant distribution and systematics in California. This outreach to other botanical institutions is an example of forming alliances with other organizations and increasing the use and relevance of the CDA Herbarium to the California community. This organization is housed at the University of California at Berkeley Herbarium (UC/JEPS) and maintains a searchable database of California herbarium specimen data. The data are available to be searched here: http://ucjeps.berkeley.edu/consortium/. The search results interface also includes a mapping function. Currently approx. 90% of the herbarium's California specimens have been databased and are searchable via the Consortium; this includes all the specimens of California weeds held in the collection. In total the Consortium database includes nearly two million searchable records of California plant locations.


Prepared by Dr. Fred Hrusa, retired Senior Plant Taxonomist.