Catkin

A catkin or ament is a slim, cylindrical flower cluster (a spike), with inconspicuous or no petals, usually wind-pollinated (anemophilous) but sometimes insect-pollinated (as in Salix).

Catkin-bearing plants include many trees or shrubs such as birch, willow, aspen, hickory, sweet chestnut, and sweetfern (Comptonia).

[4] For some time, catkins were believed to be a key synapomorphy among the proposed Hamamelididae, also known as Amentiferae (i.e., literally plants bearing aments).

[5][6] This suggests that the catkin flower arrangement has arisen at least twice independently by convergent evolution, in Fagales and in Salicaceae.

The word catkin is a loanword from the Middle Dutch katteken, meaning "kitten" (compare also German Kätzchen).