Taphrina

At this time of year it’s easy to see the cones on the almost-leafless alder trees. This year’s immature greenish-yellow cones are visible alongside last year’s open brown ones. The sight of these cones are likely familiar to many and, as such, it can be easy to walk past the trees without paying too much attention to them - but it is worth stopping next time and having a closer look. You might find a dried, brown, twisted shape emerging from some of those cones. These are clearly not part of the tree - so what are they?