Abstract

Sarracenia jonesii (mountain sweet pitcher plant) is a Federally Threatened species, and Sarracenia purpurea var. montana (mountain purple pitcher plant) is a Federal Species of Concern. Due to habitat loss, S. jonesii is occasionally outplanted into sites where S. purpurea var. montana occurs. However, anecdotal evidence and grey literature from breeders suggest that species distinctions within this genus are maintained primarily through allopatry, and that plants in sympatry hybridize readily. Observations of phenotypic hybrids at sites where these species co-occur, and genetic confirmation of hybrid parentage, led us to ask about the potential for, and realization of, interspecific breeding. In summer 2019, we monitored S. jonesii and S. purpurea var. montana at two western North Carolina field sites where they are sympatric. Parental species and their phenotypic hybrids were visited weekly during the flowering season to assess plant phenological stages and to collect anthers for pollen viability analysis; ovaries were collected after floral senescence to analyze seed production and viability. Seed collections were repeated in summer 2020. Results revealed significant overlap in flower production and stigma receptivity, and showed that pollen from both species maintained high viability even after anthers were shed. Parental species and their hybrids all produced large numbers of seeds, and seed production varied significantly by site but not by species. These data demonstrate the potential for hybridization between two species of conservation concern under field conditions, and suggest that interventions such as floral bagging should be undertaken to restrict gene flow across these permeable species boundaries. Future investigations will compare parental species’ seed production in sympatry vs. allopatry, and will discern parental versus hybrid status of the seed generation.

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