In all willows the pistillate catkins bear pods that open and let out fluffy seeds.
Ripe willow
catkin.
The cotton-wood trees are relatives of the willows. Their seeds are so very downy that when they are ripe the ground beneath the trees will often be white, as though a light snow had fallen.
It is because the seeds are so abundantly supplied with soft cottony plumes that the tree is called cotton-wood.
Poplars are also closely related to the willows and, like them, have fluffy seeds.
In the early summer, if you look in the right place, you will see plenty of them.
Willow and poplar twigs are very strong and limber, and some kinds are used to make baskets and chairs and cradles and a great many other useful things. The slender young twigs are woven together and make very strong and durable articles.
Since only the long twigs can be used, people get them in large quantities by cutting off the heads of the trees, when long sprouts shoot up all around the ends of the cut limbs. Cutting off the tops of the trees in this way is called pollarding, and a pollarded willow or poplar is rather a funny sight, particularly after it has had its head cut off a number of times.