Lambs’ tails.
Clusters of yellow catkins  looking like lambs’ tails dangle from the hazel trees now releasing their fine pollen in the breeze.  These are the male flowers but often the less obvious tiny female flowers are overlooked. They are tiny and bud-like with only the red styles and stigmas visible which are then receptive to the pollen blown from the male flowers. These then develop into clusters of nuts. To avoid self fertilisation the red female flowers appear a few days after pollen has been released by the male catkins on the same tree, so this little flower would not be fertilised by these catkins.