What is an Ament (catkin) and what does it do?

Question

What is an Ament (catkin) and what does it do?

Answer 1

It's the reproductive structure of certain trees (birches, oaks, hickory, walnut, beech, alder, hazelnut, hornbeam, hop hornbeam, willows, poplars, chestnut, etc.).  Each catkin only contains male or female flowers, which lack petals, but have small bracts (modified leaves) and these generally hang down from branches, although some types are erect.

example of a birch catkin: http://plants.usda.gov/java/largeImage?i...