Conelets all der year round

You can recognise alder trees because the little brown conelets which held last year's seeds, stay on the tree until this year's green conelets have already formed.  So they have conelets showing all der year round.

And now, in late winter / early spring, they have catkins as well, 

which will soon be turning reddish purple.

Not to be confused with the earlier, yellow catkins of hazel.