Stamen: The male reproductive organ of a flower, consisting of an anther and a filament.*
This Rhododendron dauricum ‘Arctic Pearl’ flower has 10 stamens surrounded by the petals which is typical of Rhododendrons. Although Azaleas are technically included within the genus Rhododendron, they typically only have 5 stamens. Counting the stamens is an easy way to tell these groups of plants apart.
*Harris, J.G., Harris, M.W. (2001). Plant identification terminology: An illustrated glossary (2nd ed.). Spring Lake: Spring Lake Publishing.