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Abstract: Delphinium luteum ( Ranunculaceae), an endangered larkspur, is restricted to two wild populations near Bodega Bay, California. The total number of individuals in these two populations is estimated to be <100. We used allozyme and random amplified polymorphic DNA ( RAPD) markers to (1) assess levels and patterns of genetic diversity in one wild population and two cultivated populations and (2) test the hypothesis that D. luteum is of hybrid origin between D. decorum and D. nudicaule. These data will be used to aid in developing a management plan to conserve the species. The wild population maintains high levels of genetic diversity. Genetic data indicate that both cultivated populations, especially the north Sonoma population, have several allozymes and RAPD markers not found in the wild population and could be used to establish new populations of D. luteum or to enhance the diversity and size of the wild population. The allozyme data did not reveal any fixed differences between D. decorum and D. nudicaule, although allele frequencies of the putative parental populations differed. At these loci, D. luteum resembled D. nudicaule more than D. decorum . Many unique RAPD markers distinguish each of the three species. The diagnostic markers from populations of D. nudicaule and D. decorum were not additive in the putative hybrid, and these data indicate that D. luteum is not of recent hybrid origin. Conservation of the yellow larkspur should include strategies that use the cultivated populations of D. luteum, but hybridizing D. decorum and D. nudicaule to “recreate” D. luteum is not recommended. [ABSTRACT FROM AUTHOR]

Elucidating the dynamic distribution of organismal lineages has been central to biology since the nineteenth century, yet the difficulty of combining biogeographic methods with shifts in habitat suitability remains a limitation. This integration, however, is critical to understanding geographic distributions, present and past, as well as the time-extended trajectories of lineages. Here, we link previous advances in phyloclimatic modeling to develop a framework that overcomes existing methodological gaps by predicting potential ecological and geographic overlap directly from estimated ancestral trait distributions. We show the utility of this framework by focusing on a clade in the montane angiosperm genus Heuchera, which is noteworthy in that it experienced ancient introgression from circumboreally distributed species of Mitella, lineages now ~1,300 km disjunct. Using this system, we demonstrate an application of ancestral state reconstruction to assess geographic range dynamics in a lineage lacking a fossil record. We test hypotheses regarding inferred past geographic distributions and examine the potential for ancient geographic contact. Application of this multifaceted approach suggests potential past contact between species of Heuchera and Mitella in western North America during cooler periods of the Pleistocene. Integration of niche models and phylogenetic estimates suggests that climatic cooling may have promoted range contact and gene flow between currently highly disjunct species. Our approach has wide applicability for testing hypotheses concerning organismal co-occurrences in deep time.