Willows are an angiosperm, which means they are a flowering plant species, and they have a special kind of flower called a catkin, which aids them in pollination. ... Catkins are found in some other tree species, such as birches, hickories and chestnuts.

What are catkins on a willow tree?

Most catkin-bearing trees have catkins of both sexes growing on the same tree, but in willows only a female tree can bear female flowers, fruits and seeds. Its catkins become upright, thumb-sized sausages of fluff in which each silky hair connects with infinitesimal seeds.

Which trees do catkins grow on?

Catkins play an essential role in tree reproduction and can be found on hazel, silver birch and white willow trees among other species. For a few weeks each year, catkins release pollen into blustery March breezes, then fall the leaf canopy unfolds.