Orcutt's spineflower: an update

Last year I wrote about Orcutt’s spineflower (Chorizanthe orcuttiana), a diminutive, highly endangered plant from the coastal bluffs of San Diego County. We collected 1500 seeds of this plant for our seed bank. This was part of a larger project with the Chaparral Lands Conservancy to enhance existing populations of Orcutt’s spineflower in their native range. RSABG was also involved with the second phase of this project, which was to regenerate seeds of this plant to reintroduce into the wild.

This type of work is called ex situ conservation. In a nutshell, biodiversity is taken off site where it can be regenerated or stored for long term genetic backup. This type of strategy differs from in situ conservation, in which native habitat and all of the biodiversity contained within is conserved. Establishment of wilderness areas, national parks and other wildlands are examples of in situ conservation methods. These strategies go hand in hand. As land is protected through in situ conservation, rare biodiversity can be recovered and reintroduced through ex situ conservation.

Regenerated seeds of Orcutt's spineflower

 A classic example of ex situ conservation, and one of the great successes of endangered species recovery in recent years comes from a large vulture of the west coast. In the 1980s, the population of California condor was so low that extinction seemed imminent. A seemingly audacious plan was launched, and all 22 remaining birds were taken from the wild and put into a captive breeding program. Chicks were carefully raised in an ex situ facility, and when the time was right, were introduced back into the wild. Since then, multiple reintroduction sites have been established, and the wild population is now over ten times larger than it was in the 1980s, with hundreds of additional birds still being reared in ex situ facilities.

Plants were grown at the RSABG nursery

It is always interesting to take something from the wild and observe its growth in a controlled setting. When we began our regeneration of Orcutt’s spineflower we weren’t exactly sure what the best method would be. After carefully reviewing all of the literature we could find on this species and others from the spineflower genus we came up with a propagation plan and began growing plants.  It was amazing to see the difference between these cultivated specimens and those that I saw in the field last summer in Del Mar. Our ex situ plants, which were receiving plenty of attention, water and nutrients were absolute monsters compared to their wild parents. This is the beauty of this process. You can take away all of natures variables and produce hundreds of seeds from a plant that may have only produced a few seeds in the wild. The seeds have been harvested and cleaned, and will be stored in our seed bank until they are ready for reintroduction in their coastal habitat. I am happy to say that we were successful in our first round of seed regeneration, and turned a sample of approximately 250 seeds into over 30,000 seeds of this very rare plant. 

Regenerating a Rare Sunflower

In my mind, the sunflower may be the most iconic American plant. It’s a plant of summer, a plant of fall, a plant chewed on the ball field (and a healthier one than the other plant commonly chewed on the diamond, Nicotiana tabacum). My earliest gardening memories are of a sunflower; of planting a seed in a Dixie cup with my preschool class and watching it grow in my parent’s garden till it towered over my head.  It was fitting that one of the first plants that I worked with at Rancho Santa Ana Botanic Garden (RSABG) was a sunflower.

Flowers of Helianthus inexpectatus

The seed bank at RSABG is always adding new seeds to its collection. Each of these new seed collections must be tested to make sure that the seeds are alive. There are several ways to test whether or not a seed is alive.  The method that we use for most of our seed collections is germination testing. This process is fairly straightforward. We take a small sample of seeds, and germinate them under very specific and controlled conditions. By looking at the ratio of seeds which sprout compared to the total amount of seeds which were sown and dissecting and making observation about any ungerminated seeds we can get a good estimate of the percentage of viable (living) seeds in a collection. On my first day at RSA, an assortment of interesting seeds was ready and waiting to be tested. One of these was a sunflower, and a rather unusual one…

The Newhall Ranch Sunflower (Helianthus inexpectatus) wasn’t formally described until 2010, when David Keil and Mark Elvin published a description in  Aliso, the scientific journal of RSABG. Before the description, there was some confusion about what this plant actually was. It was found at Newhall Ranch, an interesting and controversial piece of land just south of the grapevine along the I-5. When they were discovered, there was some confusion about the taxonomic identity of these plants. Based on pollen size, chromosome counts that differed from closely related species and other factors, the plants were described as an entirely new sunflower.

Since the seeds came from such an unusual plant, we used a very small sample to test their viability. 30 seeds were sown, 17 of which germinated. This gave us our baseline of viability for the collection, and the added bonus of 17 tiny plants. In some of our tests, the plants which are produced inevitably end up being discarded, often in a spectacular display of fungal attack, but with these unusual seeds we knew that we wanted to grow them on. The plants were grown in small two inch pots for several weeks and were tended to with care by our talented nursery staff. Once they were large enough, we transferred them to raised beds, where we could grow them to maturity.

Seeds of Helianthus inexpectatus

Seed regeneration, also known as seed bulking, is the process of taking a small amount of seeds, growing plants from them, and collecting and storing the seed that those plants produce. The 17 plants that were produced during germination testing were used for this purpose. After a long summer of frequent watering and the occasional threat of insect attack, the plants flowered and began to set seed. We harvested seed over the course of approximately one month, collecting mature flower heads and storing them in a dry area in paper bags. Many of the seeds were found to be unfilled and non viable, but some were healthy and normal. Altogether we were able to harvest more than 2,500 viable and healthy seeds from the 30 seeds that we started with in our germination test. The seeds that we produced will be stored at the RSABG seed bank, and will be available to the botanical researchers and conservationists. 

Susanna Bixby Bryant, the founder of RSABG, envisioned an organization that would “…replenish the depleted supply of some of the states rarest plants.” Many years after she wrote those words, it is an honor to be continuing this work, methodically collecting, storing, growing, and regenerating our states rarest plants.