Curation and Management of the RSABG's Seed Collection
The mission of the Garden is to make significant contributions to the appreciation, enjoyment, conservation, understanding and thoughtful utilization of California's natural botanical heritage.
This mission was enhanced in November 1994 when new seed processing and storage facilities were established through the generous support of the Fletcher Jones Foundation. The Fletcher Jones Education Center for the Preservation of Biodiversity complex includes cold storage for seeds, climate controlled growth chambers that facilitate germination studies and graduate program research, seed processing equipment and ample laboratory space.
The primary function of RSABG's Seed Conservation Program is the curation and management of the Garden's extensive seed collection. The collection is comprised of over 4,900 accessions representing more than 2,100 California native plant species and cultivars. These collections serve a diverse community in the conservation, botanical, research, education and horticultural fields.
Following guidelines set by the Biodiversity International, Center for Plant Conservation (CPC), and in consultation with the USDA National Center for Genetic Resource Preservation the Garden provides low humidity and low temperature long-term seed storage for the preservation of plant genetic resources. Facilities presently available include -23° Centigrade freezers as well as all of the equipment necessary to appropriately process and store seed collections.
Through a Memorandum of Understanding with the State of California Department of Fish and Game and the U.S. Fish and Wildlife Service, the Garden is authorized and regularly utilized as the principle repository for germplasm collections of rare, threatened and endangered California native plant species.
In 1985, the Garden became a charter member of the Center for Plant Conservation (CPC). One of 41 gardens and arboreta nationally, RSABG helps to maintain a national collection of some of the most critically endangered plant species. Coordinated by the CPC, regional participating institutions endeavor to place critically endangered species into cultivation and/or maintain seed collections of these plants in long-term cold storage.
In addition to preserving seeds of rare, threatened and endangered species, the Seed Conservation Program provides seeds as well as tissue samples from the Garden's living display collection for research, display and educational use at other institutions.
The following Seed Conservation Program forms and documents are available.
- Seed Collections Policy
- Botanic Gardens and Conservation
- Field Record Form
- Seed Collection and Storage Guidelines
- RSABG Seed List (Excel and PDF)
- Seed Request Form (Excel and PDF)
As various human impacts on the environment continue to reduce the abundance and distribution of many plant species even to the point of extinction, seed banking and other related ex-situ conservation strategies are becoming increasingly valuable and necessary conservation tools.
The benefits of ex-situ (off site) seed and living plant collections:
1. Ex-situ collections conserve material for habitat creation and restoration as well as for endangered species recovery projects
2. High quality genetically representative germplasm collections can serve as a fairly inexpensive insurance policy protecting our most threatened plants and their associated species from extinction.
3. Well documented collections at Botanic Gardens (plants, seeds, pollen, tissue samples) serve as a relatively inexpensive and easily accessed source of material for research use thereby protecting natural populations from the potential negative impacts of collecting and sampling.
4. Seed banks will ultimately help us to better understand both the potential and the limitations of seed storage as a conservation tool.
5. Seed and living plant collections help us to better understand horticultural requirements necessary to propagate and recover endangered species and their habitats.
6. Lastly, and most importantly, this off site germplasm incorporated into living collections and interpretive displays at botanic gardens, universities, parks and museums facilitate opportunities for increased public education and greater appreciation for our natural biotic heritage and processes.
Definition of Collections
The seed bank collections stored at RSABG, categorized by their purpose and ultimate use, are defined as follows:
Documented "conservation" collections - consisting of rare, gene pool representative germplasm collections that primarily serve to prevent extinction and as a source material for conservation research and restoration.
Documented collections - collections designated to serve general research, education and horticultural programs at RSABG as well as at other institutions through the Garden's electronic website Index Seminum program. Samples of wild collected state or federally listed plant species are not released without approval from the appropriate regulatory authorities.
Undocumented collections - collections of unknown wild parentage, from plants cultivated and harvested at RSABG on a regular basis, that serve horticultural, educational and gift shop programs.
Processing Seed Collections
After seed collections are processed and inspected for purity and viability, they are rapidly dried to equilibrium at 20° C ( 68 ° F ) and 12-15 percent RH (using silica gel desiccant). The collections are weighed, counted and packaged then the storage containers are sealed and placed into storage at -18°C (0°F). Plant species listed in the California Native Plant Society's (CNPS) "Inventory of Rare and Endangered Plants" are stored in hermetically sealed barrier foil/plastic laminate storage bags. Seed collections of more common species are stored in double sealed plastic bottles. Rare and endangered species accessions (CNPS 1B) with more than 500 seeds are packaged into three storage units: 20 percent "active" for testing and distribution; 40 percent "base" for long term undisturbed storage; 40 percent (up to 3,000 seeds) "back-up" for storage at the USDA National Center for Genetic Resource Preservation in Fort Collins, CO. Many collections of highly threatened and endangered species are maintained along maternal lines where each individual plant sampled within a population has its seed packaged separately. This collection and storage practice allows for better control of genetic representation in seed regeneration and restoration projects.
During processing, small samples of light weight seed are separated with a seed blower and then dissected under magnification and checked for healthy endosperm and/or embryo tissue. Most seed collections can be processed to achieve a minimum of 95 percent filled, sound, seed.
Standard testing procedure used at RSABG is described below. This procedure is followed for all viability tests unless seed pre-treatment, alternative temperature, light or procedural requirements are known to be necessary.
Procedure: 0.5% agar solution on sterilized styrene examination plates.
Std. test lot size: 25-100 seeds
Environment: 11 hrs. light @ 20° C / 13 hrs. dark @ 12° C
All incoming seed collections are tested to document either the level of dormancy or seedling vigor in non-dormant seeds. Follow up germination tests to monitor storage tolerance are performed as time and opportunity allow with priority given to funded conservation seed collections.
Germination References for California Native Plants
While there are many references on seed germination, the short list below are specific to germinating seeds of wild collected plants. The first three reference California species in particular. Seeds of many wild plant species often have complex dormancy that allows them to survive in their natural environment. This dormancy inhibits germination, often for decades and sometimes for centuries, until changes in the local environmental conditions, seed physiology, or seed chemistry occur shifting the seed from a state of dormancy to one of germination.
Emery, Dara E. 1988 "Seed Propagation of Native California Plants" Santa Barbara Botanic Garden
Young & Young 1986 "Collecting, Processing and Germinating Seeds of Wildland Plants" Timber Press
Young & Young 1992 "Seeds of Woody Plants in North America" Dioscorides Press
Carol C. & Jerry M. Baskin, 1998 "Seeds: Ecology, Biogeography, and Evolution of Dormancy and Germination" Academic Press
A California native plant seed processing manual
"Processing Seeds of California Native Plant" by Michael Wall and John Macdonald was developed over a 10-year period by members of the Rancho Santa Ana Botanic Garden Seed Conservation Program. The manual occupies a unique niche among seed publications because of its focus on the seed processing steps that precede - and are necessary for - successful propagation and long-term seed storage. It targets California native plants and plants native to northern Baja California, Mexico, but the general techniques will be applicable also to other physiologically or taxonomically related species. High quality, local-source germplasm collections are a critical resource for restoration, conservation and the stewardship of our natural biological communities, and this publication was developed specifically for those working in these fields. Read more about "Processing Seeds of California Native Plants" on the Garden News Blog.
To buy a copy call us at (909) 625-8767.
Index Seminum: Seed List
In keeping with the mission of the botanic garden, the seed collections of Rancho Santa Ana Botanic Garden consists primarily of species that occur within the state of California, the northern regions of Baja California, Mexico, and cultivars derived from California native plant species.
The Garden makes no claims as to the viability of seed offered through this electronic index. In addition, participants should be aware that seed from cultivated plants (Provenance Type Z or G) is derived from open pollination and no guarantee as to their purity is implied.
This seed index is published for access by botanic gardens, conservation, research, and educational institutions. Seeds from the RSABG seed bank are not distributed to private individuals. Native wildflower seeds are offered to the public through sales at the Grow Native Nursery in Claremont. A list of other commercial sources of California Native seed can be found below.
A U.S. $3.00 per packet fee* is charged to offset processing, shipping and handling costs. Important note: Orders from outside the United States must be paid by Visa or Mastercard. Requests within the U.S. may be paid by check payable to Rancho Santa Ana Botanic Garden.
Seed sample packets usually contain between 25 and 200 seeds.
California institutions offering documented wild collected seed through their Index Seminum program are exempt from fees for up to 20 packets per year.
The Index is available as a Microsoft Excel spreadsheet (241 KB)
You can use the find command to search the list. PC: (ctrl + F) Mac: (apple command + F)
This seed list was last updated in August 2016.
Organization of Seed List
The accessions are sorted in alphabetical order by genus then by accession. In all of the lists the following fields accompany each accession in the collection. For many accessions, the spreadsheet file also contains references to and allows sorting by habitat.
- ACC NUM: RSABG accession reference number
- NAME: Nomenclature primarily follows The Jepson Flora Project Online Interchange
- FAMILY: Plant Family
- PT: Provenance type
- (W) Seed collected from plants growing in native habitats
- (Z) Seed collected from plants in cultivation from known wild origin
- (G) Seed from cultivated plants not of known wild origin
- HABITAT: Plant community or habitat information on the collection site
- STORE_DT: Storage year
- ORIGIN: County of Origin
- CNPS RARE PLANT RANK: CNPS Ranking Web Site
- STATUS: Restricted collections. Collections with the following designations are either not available or are accessible for research or conservation purposes only:
- SE, ST, FE, FT: Species protected under the Federal or State Endangered Species Acts. Seed samples of these restricted taxa are not available without first securing a federal or state research permit.
- R: Available for research purposes only or restricted due to limited availability. Availability and release of samples from these collections will be determined by proposed use and quantity of seed available for distribution.
- N/A: Not available generally due to limited quantities or because the collection is part of a core Garden collection.
Placing an Order
- Send in your order using a copy of the Seed Request Form (available as a Microsoft Excel or pdf file). Please include your name, institution, shipping address, e-mail address, request date, and the required payment . Orders from outside the United States need to be paid for by Visa or Mastercard. Requests within the U.S. may also pay by check made payable to Rancho Santa Ana Botanic Garden.
- It may occasionally be necessary to substitute a different accession of the same species. If this is unacceptable please mark 'No Sub.' on the order form or indicate an acceptable substitution.
- Include a statement as to how the collections are to be used.
- Orders will be filled on a first-come, first-served basis. Due to limited quantities or prior requests, we may not be able to fill all requests.
Convention on Biological Diversity
In response to the Convention on Biological Diversity, the Garden supplies the seed requested on condition that:
- They are used for the common good in areas of research, trials, breeding, education and conservation.
- If the recipient seeks to commercialize the genetic material, its products or research derived from it, then written permission must be obtained from the Rancho Santa Ana Botanic Garden.
- The genetic material, its products or research derived from it are not to be passed on to a third party for commercialization without written permission from the Rancho Santa Ana Botanic Garden.
Seed Distribution and Invasive Exotic Plants
Rancho Santa Ana Botanic Garden is concerned about the serious impact that alien plant introductions can have on local native plant populations. It is assumed by this institution that the receiving institution or individual will not order seeds of species that might escape from their garden and become invasive weeds or through their introduction, genetically pollute local native plant populations.
Importing Seed Outside the United States
It is the goal of this institution to abide by all government restrictions regulating the import and export of seed. It is assumed that the receiving institution, in placing an order, is in compliance of any local regulations. Organizations and individuals should therefore contact the Agricultural or Plant Health authorities in their country to check on any restrictions before ordering seed.
The Garden requests copies of any publication produced with reference to this collection, as well as acknowledgment in any such publication.
The Garden would appreciate receiving any germination data obtained on seeds from our collection. In addition, any error in identification should be brought to our attention. This will help us monitor and maintain the highest standards in our Seed Storage and Index Seminum Program.
Other Sources of Native Seed
For individuals and commercial establishments seeking seed of California native plants, we recommend contacting the following commercial sources. (This list is provided for informational purposes only and no recommendation is implied).
Commercial establishments specializing in seeds of California native plants
P.O. Box 407
Bolinas, CA 94924 USA
Ph: (415) 868-9407
Theodore Payne Foundation
10459 Tuxford Street
Sun Valley, CA 91352 USA
Ph: (818) 768-1802
Tree of Life Nursery
33201 Ortega Highway
PO Box 635
San Juan Capistrano, CA 92693 USA
Ph: (949) 728-0685
PO Box 96
Freedom, CA 95019-0096
487 Dawson Drive
Camarillo, CA 93012
Ph: (800) 423-8112
Sierra Seed Supply (Custom Habitat Collected Seed)
358 Williams Valley Rd., Greenville, CA 95947
Phone & Fax: (530) 284-7926
Cultivated varieties of California species are available through the following companies
Thompson and Morgan Inc.
P.O. Box 1308
Jackson, NJ 08527-0308 USA
Ph: (800) 274-7333
Park Seed Company
1 Parkton Avenue
Greenwood, SC 29647-0001 USA
Ph: (800) 213-0076
W. Atlee Burpee Co.
300 Park Avenue
Warminster, PA 18974 USA
Ph: (800) 888-1447
Commercial establishments wholesale only
Carpenteria, CA 93013 USA
Ph: (805) 684-0436
Environmental Seed Producers
P.O. Box 2709
Lompoc, CA 93438 USA
Ph: (805) 735 8888
Stover Seed Company
P.O. Box 21448
Los Angeles, CA 90021-1390
USA (800) 621-0315
Sponsoring Seed Collections
Given that many North American botanic gardens are privately funded non-profit institutions, the success of their programs frequently depends on grants, government agency and public support. In order to protect the botanic gardens resources, funding for seed banking and other ex-situ conservation services must be incorporated into mitigation and habitat conservation plans.
This page provides information for those parties seeking to place conservation seed collections into storage at the Rancho Santa Ana Botanic Garden. The following brief program description provides the guidelines for establishing appropriate seed collections and contains information regarding: conditions of acceptance and program funding policy; general collecting guidelines; field documentation information required for accessioning and defining seed collections.
Conditions of Acceptance
- Seed collections and Seed Program services provided at RSABG are restricted to those that serve to execute and advance the mission of the Garden.
- Collections stored at RSABG as part of mitigation, habitat, or species conservation plans must be funded. Financial support of all collections stored at RSA is encouraged. RSABG reserves the right to deny acceptance, return, or dispose of non-funded seed collections. See our schedule of Seed Processing and Storage Fees.
- Seed collections deposited at RSABG for permanent storage or use are accessioned as part of the Garden's collection and become the property of the Garden.
- Seed collections accepted at RSABG are stored without condition. RSA cannot be held financially responsible for loss in seed viability or for loss of or damage to a seed collection. The Garden cannot guarantee to maintain the viability of the seed collection. Seed re-collection or horticultural re-generation, if required to restore viability of a collection, is not covered under these guidelines.
- Seed collections must be legal collections.
- Seed collections must be high quality collections.
- Voucher specimens are necessary for all new accessions. If a previous voucher exists indicate the reference number and institution where it resides.
Collection and Documentation Guidelines
Seed collection sampling protocols will vary for different species; variants include the size and existing threats to a plant population, the current season seed production and the purpose of the seed collection. Contact the Seed Curator for assistance in designing the most appropriate sampling protocol. Seed collections sent to RSABG for storage should adhere to the following general guidelines and be submitted with the specified information and documentation.
Ethics and legalities:
Collections must be made with permission of any land owner or land management agency and must adhere to the guidelines set by any applicable local state and federal laws. This includes obtaining any required state and/or federal permits and adhering to the conditions set by the permit(s). Copies of any required permits and/or agency authorization must accompany the seed collection.
Include a statement of rationale or purpose for seed banking the species, i.e. program donation for institutional use, to establish a permanent conservation collection, mitigation for impending or anticipated impacts to the population, etc.
Detailed collection information is critical to accession, define, and document a collection. A copy of RSABG’s Field Record Form is available to be filled out online and submitted through email (download via the link above for download forms page). Copies of any permits and/or mitigation requirements associated with the seed collection are also required. Where possible a photocopy of a USGS topographic map with the collection site and the population distribution identified should accompany the collection. A voucher specimen is an important component of a collection’s documentation and should be sent with the seeds. If a voucher specimen already exists, please provide the name of the institution where the specimen is deposited and the collector’s collection number. Seed generated from plants in cultivation need to have similar documentation including but not limited to: wild origin lineage data, number of maternal individuals represented in the seed collection and reference to a vouchered wild collection.
For high quality "conservation collections", the sampling of a population should be conducted in a manner that optimally captures the genetic diversity of the population without harming the plant populations' long term viability. Depending upon the purpose and ultimate use of the seed collection, collections can be made consisting of seed from all individuals sampled within the population - i.e. a bulk sampled collection - or a maternal line sampled collection can be made where seeds from each individual sampled in the population are kept separate. Where collections are to be used for seed regeneration and future plant restoration projects, storing seed along maternal lines will enable the researcher to control and therefore maximize the number of parental individuals contributing to the regenerated seed collection.
The size of the seed collection will ultimately depend on the purpose of the collection, collection timing, the size of the plant population, the quantity and quality of seeds that each plant produces and the taxa itself. For high quality conservation collections, in general we recommend sending a minimum of 2,500 seeds per population from 50 individuals randomly sampled throughout the population’s distribution. Obviously situations exist where a collection of this size would not be practical or could negatively impact the population. In instances where a collection would have to be made from very small and/or unproductive populations, a smaller percentage of the seeds should be collected with the plan of recollecting in the future.
It is typical for different individuals within a population to produce more seeds than others; therefore it is important not to bias a "bulk seed" collection in favor of these unusually productive individuals. Where it is deemed necessary to take advantage of the seed production from these fecund individuals, those samples should be kept separate from the rest of the collections.
It is important to note in the field whether the seeds that are being collected have viable embryos. Many instances occur where a high percentage of seed consist of only an empty seed coat or have been heavily parasitized. In this situation a larger seed collection would be necessary. Fully ripened mature seed is going to have the highest viability, the most vigor, and the greatest longevity in storage. While it is sometimes possible to collect immature fruits whose seed finishes ripening while attached to the harvested stems in the collection bag, this collection method should be avoided for important conservation collections and fully ripe seeds should be the goal.
Temporary Storage and Shipping:
After harvest, most seeds and/or fruits should be loosely packaged in well sealed breathable paper bags or envelopes and sent to RSABG for processing as soon as possible. Plastic containers are acceptable for shipping if seeds and/or fruits are completely dry. To avoid molding, moist fruits should be loosely packed in a plastic container and shipped overnight or received the following day. Post harvest care of the seeds is critical and every effort should be made to keep the seeds under moderate (room) temperature and relatively low humidity until they can be shipped. Make certain that all collection bags and envelopes are well labeled.
For rare plant collections, collectors are encouraged to submit a Natural Diversity Data Base Native Species Field Survey Form to the California Department of Fish and Game. For general information on the Natural Diversity Data Base or for copies of the Field Survey Form contact:
California Department of Fish and Game
1416 Ninth Street, 12th Floor
Sacramento, CA 95814
or call (916) 327-5956.
The CNDDB Field Survey Form is also available as a PDF file on-line.
For additional information on making high quality seed collections see our Seed Collection Guidelines (available on our download forms page linked above).
RSABG Seed Image Database
In September 2010, RSABG volunteer John Macdonald photographed spores of Woodsia scopulina (a member of the wood fern family), the last species in the Rancho Santa Ana Botanic Garden germplasm collections to be photographed.
Macdonald now has photographed seeds or spores of all of the Seed Conservation Program’s 1,500 California native species and another hundred or so varieties and subspecies.
Altogether he has close to 2,000 seed images. He maintains the website that houses these images for public accessibility.
Macdonald’s seed image website has the seed size, date taken and accession number for reference. He also prints copies of each image and these are stored in file cabinets in the seed lab. If his printed seed images were displayed side by side they would run for over a third of a mile.
So what's next?
In addition to photographing any new taxa that come into our collections He will be re-shooting and improving the quality of some of the early images using the techniques that he has developed over the past several years.
Seed Conservation Program History
Many of the historical references for this summary were acquired from Dr. Lee Lenz' 50th anniversary issue of Aliso or from personal recollections that Dr. Lenz was generous in sharing. Additional information was gleaned RSABG newsletters, Seed Program file records and personal communications with staff members. Those who are so inclined are invited to submit additional information that would enhance the value of this narrative. Clarification of any discrepancies or inaccuracies would also be greatly appreciated and will be included in future issues of the Seed List.
Why a Seed Bank?
In the National Geographic publication "Nature’s Medicine Plants That Heal" author Joel Swerdlow writes that nearly 400 years ago, William Shakespeare described plants as part of nature’s “infinite book of secrecy.” With the rapid advances in science and technology developed during the 20th century we are only now beginning to discover what secrets lie hidden within nature. Unfortunately, just as we are gaining the necessary technology and interest, the pages and text from this great ‘book of secrets’ are rapidly disappearing. In an effort to slow down this loss - government agencies, grassroots conservation organizations and botanical institutions are investing heavily in the preservation of these pages of genetic information by maintaining living plant collections and the establishment of seed banks.
Seed Collecting and Storage at RSABG - 1927 to 1977
In a 1941 report, Carl Wolf, the Garden’s first staff botanist, noted that between 27 April and 16 August of that year he had spent 57 days in the field and had traveled 8,000 miles, making 1,100 herbarium specimens and several hundred lots of propagation material. Later in his statement Mr. Wolf affirms, "As you read my report covering field work you may wonder that such large amounts of time and energy have been given over to this phase of the Garden's activities. However, it should be remembered, that, unlike many other botanic gardens, this one is greatly dependent upon fieldwork for the attainment of its goals. Therefore, nearly all the other Garden activities are more or less directly proportionate to the amount of field work, which includes the collection of data, specimens and propagation materials." Aliso, 1977 "RSABG The First 50 years," pg. 65. Carl Wolf, Edward K. Balls and Percy Everett, were three of the Garden’s most prolific field collectors, and their names are the ones most frequently associated with the Garden’s early collections. Edward K. Balls, a native of Yorkshire, England, came to the Garden in 1949 first working as a groundsman and then horticulturist. According to Director Emeritus and Garden Historian Dr. Lee Lenz, Edward K. Balls was "A true collector in the best sense of the term. Under his direction the seed collection took on major proportions" (Aliso, 1977) and Edward Balls was "The best seed collector, the most broadly educated, cultured, and sadly underrated staff member we ever had." (per. comm.) Although these gentleman’s seed collections are no longer in storage at RSABG, many treasured ‘heritage plantings’ still exist today and serve as living memorials to these venerated plantsmen who dedicated their careers and creative energy to building the collections of the Garden.
Although the collection of wild originated propagation materials has always been the foundation of the Garden’s collections seeds have historically also been collected from plants cultivated at RSABG. Dr. Lenz, reflecting back upon his coming to the Garden said, "From the very beginning seed was collected in the Garden. The long rows of carefully cultivated godetias, poppies, etc. were a major attraction for visitors to the Garden, similar to the commercial fields around Lompoc, etc. We have never had anything equal to them since. The original field was perhaps a quarter acre in size, perhaps less. Allen Chickering, then chairman of the board, and I were standing in the wildflower field one beautiful evening in April when he offered me a position at the Garden." (L. Lenz per. comm.)
As at the old Garden site, in the early days at Claremont, large quantities of seed were harvested from the expansive annual cover plantings that served to fill in the open areas as the perennial plantings took hold and developed. These quite massive Garden collections, along with the smaller yet extensive wild collected seed lots, were stored until needed in large metal drums and glass mason jars in the seed storage room at the old Garden site in Santa Ana Canyon. Soon after the Garden moved to Claremont in 1951, the Stone House that was originally a rest room for the golf course, became the new Seed Storage building. Situated in the cool air sink area east of Indian Hill Mesa, this structure with its thick, insulating rock walls, was thought to afford a moderated storage environment ideal for seed storage. (per. comm. L. Lenz, W. Wisura)
Early Index Seminum Program at RSABG
Participating in what is close to a 300 year old botanic garden tradition (the first Index Seminum was circulated by Jacob Bobart, the Younger, in 1702) the Garden also utilized these extensive seed collections for distribution in the Garden’s own Index Seminum or seed exchange program. A 1954 seed list is the oldest record of the Garden’s Index Seminum Program on file. Dr. Lenz said, “It is unknown when the first Index Seminum was published but they were originally done on a mimeograph machine with a very limited distribution”. In the 1954 Index, 587 taxa are listed - a truly extensive offering for such a young institution. A 1957 Seed List was the first to identify wild and garden collected seed accessions. The total number of species offered in this Index was 525 taxa; 162 identified as wild collected and 363 species collected from plants in cultivation at RSA. Although they were most likely responsible for earlier indexes, the 1966 Index Seminum was the first to note Percy Everett and Dr. Lenz as producers of the Index.
(University of Oxford Botanic Garden Seed List 1999)
The oldest of the Garden’s seed collections still in existence are those that, as part of the Went/Munz long- term seed longevity experiment, now reside at the U.S.D.A. National Seed Storage Laboratory in Fort Collins, CO. In 1998, after 50 years in storage, viability tests on these seeds were conducted. Staff at the nation’s federal germplasm repository are currently in the process of preparing their findings for publication and a summary of their results along with the reference for this publication will be noted in the next Seed List.
Seed Collecting and Storage - 1977 to the Present
Certainly the three most prominent Garden collectors since the mid 1970s were Walter Wisura, Orlando Mistretta and Bart O’Brien. Traveling and collecting extensively throughout the state, the Southern Channel Islands and Baja California, these three individuals have contributed or were indirectly responsible for the bulk of the collections that are in the Seed Bank today.
In search of a replacement for Warren Sullivan, long-serving plant propagator and nursery manager from 1945 – 1974, Walter Wisura was persuaded to leave behind a prominent and very successful horticultural and botanical position in South Africa at the prestigious Kirstenbosch Botanic Garden and join the Garden staff at RSABG. During his 18 year tenure at RSABG (1977 – 1995) Mr. Wisura served principally as Plant Propagator and as Curator of the Living Collections. Classically trained in the European botanic garden traditions, he was dedicated to incorporating the high curatorial standards that make the Garden’s collections the scientific assets they are today. Prior to the establishment of an Endangered Species Program Walter Wisura also initiated and coordinated many of the Garden’s early conservation seed collections.
The Index Seminum Program - 1977 to the Present
In 1977, at the request of Horticulturist Clarence ‘Dick’ Tilforth, Walter Wisura took on the responsibility of managing the Garden’s Index Seminum program. From 1977 until his retirement in 1995 Mr. Wisura collected much of the seed, coordinated the distribution of the Index to hundreds of botanic gardens, and processed the many requests for these high quality and well documented seed collections.
The 1996 Index Seminum was the last printed version to be distributed. In 1997, with the assistance of Garden associate professor Dr. Curtis Clark, the Index Seminum that now included the entire seed collection would from this point forward be published on the Garden’s internet website. In implementing the new 'Electronic' Seed Index, the Garden sought to reduce production and distribution costs associated with this activity. At the same time this would improve accessibility to the collections by research, conservation and botanical institutions worldwide.
The Beginnings of a Seed Bank at RSABG
In 1984, under the leadership of Executive Director Dr. Tom Elias, the Garden was prominently involved in the establishment of the Center for Plant Conservation - a national coalition of botanic gardens operating programs in plant conservation. In 1988, Orlando Mistretta, a recent graduate of the Claremont Graduate School in Botany, was offered the position as Endangered Species Coordinator. Mr. Mistretta should be acknowledged as the principal botanist at RSABG responsible for researching and initiating improved seed storage practices, for laying the foundation and setting the course that the Garden would follow in establishing a seed bank and other conservation programs. A compassionate and energetic individual, he was from the beginning actively involved in the development of the CPC program and was highly respected among his peers in the early development of the botanic garden conservation movement.
In 1988, to extend the longevity of the Garden’s rapidly growing and increasingly valuable seed collections, an upright refrigeration unit and a chest style freezer were purchased and installed in the stone house. (RSA Annual Report, 1987 - 1988) At this point Walter Wisura coordinated the transfer of the horticultural seed collections from the glass Mason jars into double sealed plastic storage bottles. These seed collections were then placed into medium term storage (MTS) conditions (5 °C / 41 ° F). Orlando Mistretta, assisted by technicians Mike Hammitt and later Kitty Blassey, processed the seed collections of rare, threatened or endangered species that, following 2 to 3 weeks storage at 12 percent relative humidity, were packaged and sealed in “Crystal Springs” storage pouches and placed into long term storage (LTS) conditions (-18 ° C / 0 ° F). It was customary during this period for seed collections of rare but non-listed plant species to be split between the Horticulture MTS collections and the Endangered Species Program LTS collections.
In 1990, Bart O’Brien was hired as director of horticulture. A talented and intuitive plantsman O'Brien brought to the Garden a strong knowledge of horticulture, the California flora and considerable interest in, and enthusiasm for, the unique mission and collections at RSABG. Like many of his predecessors, O’Brien traveled and collected extensively throughout the state. During this time, the early to mid 1990s, the seed bank collection grew rapidly. He continues today to add to the Garden’s ever-expanding and valuable plant and seed collections.
New Directions in the Seed Program
The mid to late 1990s were also a period of considerable change in the operations and management of the budding seed storage program. With the completion of the new Horticulture Complex in 1995, both the MTS cold storage and the LTS sub-zero storage units were moved into the new and spacious Fletcher Jones Seed Storage facility. Curation and management of both the Horticulture and Endangered Species Program seed collections were now primarily under the stewardship of Orlando Mistretta and newly hired part time Seed Technologist Mark Elvin. Soon after returning from a trip to the Royal Botanic Gardens at Kew and the seed storage facilities at Wakehurst Place, Mistretta and Elvin initiated moisture permeability tests comparing the ‘Crystal Springs’ and the heavy duty foil plastic laminate storage pouches used at ‘Kew Gardens’. At the same time Dr. Ed Guerrant at the Berry Botanic Garden conducted parallel tests on these seed storage pouches. With the superior performance of the ‘Kew’ bags confirmed by both institutions, Seed Program staff began the transfer of the LTS seed collections into the new ‘Kew’ storage bags. It was during this period and through 1996, that Seed Technician Elvin also placed many of the LTS collections into heat sealed Pyrex test tubes.
In late 1995, soon after Walter Wisura retired from his position as Curator of the Living Collections, RSABG Horticulturist Michael Wall was offered the position of Seed Curator. In 1996 Endangered Species Coordinator Orlando Mistretta resigned his position at the Garden and Mark Elvin was promoted to manage the program. In 1997, upon Elvin’s departure, Wall took over as seed program manager. During this tumultuous but productive period, institutional support for the program never waned and improvements in the curation and management of the collections continued. In 1998 two additional freezers were purchased and the Horticulture MTS collections were placed into LTS -18 ° C storage conditions. The transfer of the older LTS collections from the ‘Crystal Springs’ storage pouches was completed. Soon thereafter, with the computer network of the Horticultural Complex, seed collection record keeping and data management was greatly enhanced. Due to high material costs, accessibility limitations, and in an effort to implement a single standardized packaging protocol for rare species, the use of the Pyrex tubes for seed storage was discontinued.
A brief summary of current storage protocols at the RSABG Seed Bank are as follows:
- Following cleaning, samples of seeds are dissected and examined under magnification to assess potential viability and the quality of the seed collection.
- CNPS list species seed collections are packaged in foil plastic laminate heat-sealed 'Kew' bags while non-CNPS list species seeds are placed into double-sealed screw cap plastic storage bottles. Depending on the quantity and rarity of the collection, some seed accessions are split into active, base, and back-up components. A sample for initial viability testing is also set aside at this time. Follow-up viability testing is conducted as time, opportunity and resources permit.
- Open containers of seeds are then placed into closed chambers over Calcium Sulfate desiccant for a minimum of two to three weeks storage at 12 percent RH before being sealed and placed into the Program freezers.
- The 3 Seed Bank freezers are set at their lowest range of between -18 ° and -20° centigrade. These units are connected to a back up generator that starts automatically and will supply electricity to keep the freezers in operation in the event of a power outage.
Today at RSABG, the development, operation and management of the Garden’s Seed Program, including the acquisition of collections, is truly a cross-programmatic endeavor. It is this collaborative and cooperative work among Garden staff, volunteers, and increasingly, Garden associations outside the institution, that is the strength and support behind the production of this Seed List, the curation of the collection and the overall value and success of the program.