Saving Sweet-Scented Pigeon Wings

The Rare Plant Conservation Program (RPCP) is collaborating with the Center for Plant Conservation for a statewide initiative to preserve seeds from species not currently represented in conservation collections. The RPCP has chosen three species for this project, one of which includes the federally threatened and Florida endemic, sweet-scented pigeon wings, Clitoria fragrans (Fabaceae) (Small). C. fragrans is a narrowly distributed perennial herb found primarily in fire adapted upland xeric habitats along the Lake Wales Ridge in Central Florida. Anthropogenic activities that pose threats to populations of this species include habitat loss due to agriculture and residential development, and fire suppression that leads to impaired quality of the remaining habitat. Like many species that inhabit fire-prone landscapes, C. fragrans rebounds quickly following fire events and flowers prolifically. It is a sight to behold to see these beautiful purple flowers speckled amongst the charred black landscape.

A wild population of C. fragrans exists among the natural areas at Bok Tower Gardens, and is from this population that seeds for project are being collected. In August, 51 drawstring organza bags were placed over the fruits of different maternal parents to ensure that the seed collection will comprise a good sampling of the population’s genetic diversity. When the fruits ripen and dry, an internal mechanism twists the fruits open, ejecting the seeds from the parent plant. This seed dispersal mechanism is a shared trait of members in Fabaceae, and is an adaptation to disperse the seeds more widely than if they were just dispersed by gravity, and serves as a means to expand the population into new areas. Seeds of species of Clitoria also have another interesting feature: the seed coat is sticky. This feature may aid in dispersal, as it can make the seeds easily stick to animals, although the true function of this remains a mystery.

As for the seed being collected from at Bok Tower Gardens, once the seeds are mature they will be removed from the bags and counted. Seeds will be kept separate by maternal line. A subset of the seeds will remain in the National Collection seed storage facilities at the Gardens. The rest of the seeds will be packaged and sent to the National Laboratory for Genetic Resources Preservation for long-term storage to fulfill the goal of preserving seeds of this species under the Center for Plant Conservation project.