Pollination syndromes are an excellent area to study convergent evolution and to test whether genetic and developmental parallelism complement this striking phenotypic parallelism. Flower corolla width is a particular pollination syndrome trait that plays a role in determining which pollinators are able to “fit” the flower from a pollinator’s perspective and efficiently move pollen between conspecifics. Narrow corolla tubes, which are specialized to transfer pollen to and from a hummingbird’s forehead as its bill reaches for nectar, can exclude bees through preventing them to enter the flower. In Penstemon, shifts from bee pollination syndrome to hummingbird pollination syndrome often leads to a significant narrowing of the corolla tube. Penstemon is an exceptionally ideal system to study genetic and developmental parallelism in convergent evolution because within this ancestrally bee-pollinated genus of around 300 species, hummingbird pollination has evolved 11-20 times. Through quantitative trait loci (QTL) mapping, I aim to identify the genomic locations underlying the parallel floral corolla width differences in two independent origins of hummingbird pollination in Penstemon: P. amphorellae and its close relative P. kunthii, and in P. neomexicanus (bee pollinated) and its close relative P. barbatus (hummingbird pollinated). Once genomic regions are identified, I will determine whether a similar genetic basis for the independent origins of this parallel hummingbird pollination trait exists through assessment of QTL correspondence. Testing for QTL correspondence between the two distinct Penstemon mapping populations will reveal whether parallel evolutionary shifts are likely responsible for the striking parallel shifts in floral width traits we see.