Rare plant conservation involves a great deal of preliminary work. Prior to introducing a new population in the wild, for example, it can take months to study the habitat requirements, seed biology, and basic lifecycle and demographics of an unfamiliar species, before knowing how best to propagate and transplant plants. Embarking on seed collection for ex situ preservation requires first learning the reproductive versus the overall size of the population, and assessing the percentage of seeds that can be safely collected from any one plant, as well as the population as a whole, without negatively impacting population resiliency and demographics. The seasonal changes of a species, especially the timing of seed ripening and seed drop, and whether these vary for the different populations across its range, also need to be known.
The Rare Plant Conservation Program recently initiated preliminary work for the collection of seeds and leaves of Florida jointweed, Polygonella basiramia, under a new partnership with Atlanta Botanical Garden and the Southeastern Plant Conservation Alliance. Florida jointweed is a state endangered species that is found only in sand pine scrub at higher elevations of Polk and Highlands Counties. It is a perennial, slender herb with tiny leaves and grows up to 32 inches tall. Slender flower spikes with white petals emerge from near the tops of the stems in late summer and into the fall.
Historical population records were reviewed, target populations were identified, land managers were contacted, and permits were secured. Regional biologists and publications were consulted for information about the species, which indicated an optimum timeframe for seed collection to be January. However, general seed ripening times are only an approximation. The timing of both flowering and fruiting can vary from year to year. Although the timing of flowering and subsequent seed production is typically cued by photoperiod, weather can also play a strong role in both the onset of flowering and the timing of seed maturation for many species.
In mid-December, the Rare Plant Conservation Program visited a Florida jointweed population in Lakeland in order to track the timing of seed production for 2023. Surprisingly, the stems were bare, with the seeds having already ripened and dropped from the plants. But, due to the preplanning done in 2023, a broader window for seed collection is now established, and the project is ready to be seamlessly accomplished in 2024.
Article written by Cheryl Peterson, Conservation Program Manager. Photos by Chico Rivera, Rare Plant Specialist