UCLA

Abstract—Species in the genusIpomoeaare often difficult to identify due to their similar morphologies and their ability to hybridize with one another. An undescribed North AmericanIpomoeamorphotype inIpomoeaseriesBatatas, referred here asIpomoeaCarolina morphotype, was found to be morphologically, genetically, and reproductively isolated from other locally co-occurringIpomoeaspecies. A previous phylogenetic analysis that included a broader sampling of species inIpomoeaseriesBatatassuggested thatIpomoeaCarolina morphotype may beIpomoea grandifolia, a species described as found only in South America. To evaluate these findings, we tested intrinsic cross-compatibility betweenIpomoeaCarolina morphotype andI. grandifoliaas well as with three other co-localizing North AmericanIpomoeaspecies:Ipomoea cordatotriloba,Ipomoea lacunosa, andIpomoea leucantha. We also examined genetic differentiation using single nucleotide polymorphisms from leaf transcriptomes from multiple individuals of all five species and several outgroup species. We find no cross-incompatibility and little genetic differentiation betweenIpomoeaCarolina morphotype andIpomoea grandifolia, suggesting thatIpomoeaCarolina morphotype is a representative ofIpomoea grandifolia. This finding raises additional questions about the origins ofIpomoea grandifoliain North America and how its disjunct distribution could play a role in the divergence ofIpomoea grandifoliain the future.