Abstract: As sessile organisms, plants rely on outside vectors such as water, air, and animals to transfer male gametes to female receptors. An important consideration in the evolution of floral syndromes is the efficiency of the pollinators for a given population of plants, as floral syndromes are currently defined as being a suite of floral characteristics symptomatic of a flower pollinated by a given class of pollinators. Using data collected by myself on Silene virginica (bird-syndrome flower) in 2005 and data collected on Silene stellata (moth-syndrome flower) by Reynolds, Dudash, and Fenster in 2004, I compared the pollinator efficiency of hummingbirds on S. virginica , nocturnal pollinators (moths, mostly Noctuidae) on S. stellata , and diurnal pollinators (bees) on S. stellata . Efficiency was determined as pollen deposited divided by pollen removed. Hummingbirds are the most efficient pollinators of the three groups, with an efficiency of 2.07%. Nocturnal S. stellata pollinators had an efficiency of 0.73%. Diurnal S. stellata pollinators had an efficiency of 0.25%. This supports my belief that S. virginica evolved to a bird-syndrome flower from a bee- or moth-syndrome flower because of selection pressure from hummingbirds' greater efficiency as pollinators. While these two species evolved to be better adapted to their most important pollinators, even after generations of adaptive evolution, hummingbirds remain the most efficient pollinators.