Alder trees are now in flower, their wind-borne pollen contributing to the misery of hay-fever sufferers. This photo shows the male and female catkins and a pair of last year's mature cones.
Alder flowers form in the autumn and are dormant over the winter. The male and female catkins and the buds all have a bluish purple colour.
The male catkins mature early in the spring.
The female flowers are small but attractive in close up. Pollination is mostly by wind and it looks as though there is a lot of pollen on this flower.
The male catkins hang from the very tips of the branches to catch the breeze.