Cryptic natural hybridization between two species of Protea

Protea punctata and P. venusta are closely related, but morphologically distinct, species that naturally hybridize in the wild. Here we examined patterns of hybridization and cryptic introgression in seedlings grown from seeds collected at Blesberg Mountain in the Swartberg Mountain range. We used restriction site associated genotyping by sequencing (RAD-Seq) to identify 7185 single nucleotide polymorphisms (SNPs) to characterize genetic identity. We found evidence for extensive introgression in seedlings within maternal families, more than can be explained by mating between pure parental species. We conclude that there is cryptic introgression between these two species and that morphological identification in the field underestimates the extent of hybridization in this system.