Alders have both male and female catkins, and it's the fertilized female catkins that resemble miniature conifer cones. Male catkins hang tassel-like under the branches, while the smaller female buds grown on top of the branches. After fertilization, the female catkin develops into a small woody cone. Tucked inside its small scales are tiny seeds, which will eventually be dispersed by the wind.
Oh, and I started my 3:00 talks at three o'clock.