Flowers of Florida Ziziphus coat almost every leafless branch when at peak flowering. Photo credit Cheryl Peters

Winter for most of the United States is defined by cold temperatures, leafless trees, and in some states, lots of snow. Most flora and fauna have gone dormant or are hibernating, awaiting warmer spring temperatures. For many field biologists, this slowdown is a time to catch up on data processing and plan for the upcoming field season. But scientists in Archbold’s Plant Ecology Program are not afforded this leisure; they are hard at work collecting annual data on one of the Lake Wales Ridge’s rarest and most imperiled plant species, the Florida Ziziphus. “This plant was once declared extinct,” remarks Research Assistant Stephanie Koontz, “but once scientists and naturalists within the community started to look for it again, they discovered a handful of wild populations! We are now working hard to help bring this species back from the brink of extinction.”

The Florida Ziziphus is a large shrub with zigzagging stems and small, needle-like thorns. While it is mostly deciduous, losing its leaves during winter months, it is not dormant. Flowers begin appearing on leafless twigs in late December and into January. “The whole plant just becomes covered with tiny, light cream colored flowers that add a sweetness to the air, similar to vanilla. There is a tale that the largest population was actually discovered because a naturalist in the area could smell the flowers!” exclaims Koontz.

Even with the rediscovery of wild populations, this imperiled species is far from being declared recovered. “While wild populations are still being found (the most recent in 2017), they tend to be small, with only 15 – 25 individuals,” describes Program Director Eric Menges. “Furthermore, these populations typically are all genetically identical, clones of the same plant formed from underground root shoots. So while it may look like we have hundreds of Florida Ziziphus plants, in truth, there are only a few dozen genetically distinct individuals.” Low genetic diversity severely impacts many rare species as it inhibits their ability to successfully produce offspring for the next generation. Indeed, most wild Florida Ziziphus populations are unable to produce seeds because pollen carried by insect pollinators within the same clone does not produce seeds. Pollen must come from a genetically different plant to make a good seed, but in some cases, unique individuals can be miles apart, too far for pollinators to travel.

With this hurdle, scientists from Archbold have teamed up with geneticists from the Missouri Botanical Gardens and biologists from Bok Tower Gardens in Lake Wales to propagate genetically unique individuals for translocations, or planting out to new locations in the wild. “These propagated plants serve many purposes,” explains Koontz. “Some are planted out in nature within existing wild populations to increase genetic diversity and, hopefully, create more, good seeds. Others are used to create new Florida Ziziphus populations on strategically located conservation lands to help pollinators across wild populations. Our goal is recovery, to continue to bring this species back from the brink of extinction.” The efforts of Archbold scientists and their collaborators have been successful in creating new Florida Ziziphus populations, but most of these populations have not yet recruited new individuals from seed. The work is far from over. Every two years, scientists from all over the US meet at Archbold to strategize on how to save this endangered plant.

If you would like to see Florida Ziziphus, you can view it at Bok Tower Gardens in their Endangered Plant Garden, along with many other Florida plants in need of a little help from their friends, pulling them back from the brink of extinction.

Written By Stephanie Koontz

 Research Interns pose with a large Florida Ziziphus plant after taking basic size measurements to monitor changes in growth. This plant is from one of the discovered wild populations. Photo credit Stacy Smith.

Fruits of Florida Ziziphus from a plant at Bok Tower Gardens, where many genetically unique individuals were planted to conserve the genetic diversity. With so many sources of pollen, plants at Bok are typically heavy with fruit, each with a single, good seed stored safely inside. Photo credit Stephanie Koontz.