Catkins are elongated, cylindrical clusters of flowers that appear on certain trees and shrubs, primarily in the Salicaceae family, which includes willows and poplars. They are typically wind-pollinated and can be found in various colors, including green, yellow, and brown. Catkins usually emerge in early spring before the leaves, providing an important source of pollen for early pollinators. These structures are often unisexual, meaning they can be either male or female. Male catkins produce pollen, while female catkins develop into seed-bearing structures. Catkins play a crucial role in the reproductive cycle of these plants, ensuring the continuation of their species.