This geranium is having sex right now, before your very eyes. Those little grains of pollen clinging to the flower's stigma are competing to plunge their genetic material deep into this flower and reproduce.
National Geographic photographer Martin Oeggerli took a series of gorgeous, and (oddly) recognizably sexual photographs of pollen in action. In this gallery - and many other photographs of his in the National Geographic gallery - you can see how the plant sexual cycle works. From feather-borne pollen to a piece of pollen that is growing a sperm injector, every kind of flower smut is represented.
You can see more of Oeggerli's work on his website.
Forget Me Not
Indian mallow - this pollen shape is designed to stick to bird wings.
Snowball blossom - pollen has fallen into the stigma of another snowball blossom, and the pollen is swelling with water. One pollen grain is growing a tube that can inject sperm into the flower.
Willow - this piece of pollen will die, because it got trapped between two petals before pollenating anything.