Seed banking Orcutt's spineflower

Orcutt's spineflower (Chorizanthe orcuttiana)

At first glance it may not be the most breathtaking example of California’s botanical diversity, but Orcutt’s spine flower (Chorizanthe orcuttiana) finds itself amongst the states rarest plant species. This small prostate annual in the Buckwheat family (Polygonaceae) is endemic to coastal San Diego County, where it occurs in sandy soils, primarily in association with sandstone bluffs and southern maritime chaparral. With a listing of ‘Endangered” by both the federal Fish and Wildlife service and the California Department of Fish and Wildlife (CDFW), Orcutt’s spineflower receives the highest level of legal protection. Plants of this rarity are continuously monitored for, and the results are tracked by the CDFW. As of July 2013, 14 occurrences of this species are recorded, with only seven of these having been observed since 1980.

A major goal for the Rancho Santa Ana (RSA) seed bank is to maintain viable seed collections of the states rarest plants. Prior to this season, only one population of Orcutt’s spineflower had been collected and put into long term storage at RSA. In 2013, we are targeting this species for ex situ preservation and have accessioned two new seed collections representing previously uncollected populations into the RSA seedbank. The first collection came from Naval Base Point Loma, under a program administered by the Center for Plant Conservation which seeks to store seeds of endangered plants found on Department of Defense lands. The seeds arrived as most collections do, mixed with bits of stems, twigs, and other chaff. Seed program staff, volunteers and interns quickly set to meticulously removing anything that was not a viable seed. Twenty seeds were set aside to be germinated to assess the overall viability, and the rest were placed in our dryer tanks, to be prepared to freeze for long term storage.

Orcutt's spineflower habitat

The second collection was made at Torrey Pines Reserve in Del Mar. RSA staff members Evan Meyer and Duncan Bell met up with David Hogan of The Chaparral Lands Conservancy and Margaret Fillius of Torrey Pines Reserve to collect the seeds. This collection was made on maternal lines, which means that each individual plant was collected and will be stored separately, allowing the maximum research and restoration use. As we collected, we had to be on the look out for the Prostrate spineflower (Chorizanthe procumbens), a more common cousin of Orcutt’s spineflower. The pale green foliage and higher number of involucre spines of the Prostrate spineflower made distinguishing these tiny annuals relatively easy, although we had to work slow and make sure we didn’t collect the wrong plant. After we finished the seed collection, we took a few minutes to admire the beautiful coastal landscape and interesting plants such as Short leaved dudleya (Dudleya brevifolia) and White coast ceanothus (Ceanothus verrucosus).

With the seeds back in the lab, and a little more experience cleaning this species, we were able to quickly get the seeds cleaned and processed for storage. The next step was to germinate a small sample of seeds to test viability. Seeds of spineflowers are found within a fibrous involucre (with attached teeth or spines, hence the common name). We felt that the involucres would impede germination and increase the likelihood of mold contamination as we germinated the seeds. Under the dissecting scope, with fine tweezers and surgical scalpel in hand, intern Monica Rodriquez skillfully removed the fragile seeds from the involucres. The seeds were then sewn on clear agar plates. Within a week, every seed germinated, indicating that there is no dormancy in fresh seed and that the viability is 100%.

Creating a seed bank is one of many actions that will help protect Orcutt’s spineflower from the very real threat of extinction. This tiny plant is getting big help from Rancho Santa Ana and other plant conservation organizations.