Turning over an old leaf

If you were visiting Conwy on Saturday afternoon and wondered why some of us were peering intensely at the undersides of leaves, the answer is... Rust Fungi!

Expert mycologist Debbie Evans ran a workshop here to share her passion for what are probably the most overlooked organisms on the reserve, or in the countryside, yet I bet we've all seen them. Rust fungi are pathogenic fungi, and around 250 different species have been recorded in the UK, many being unique to a particular host plant. They live on healthy, vigorously growing plants, and often do not cause wild plants any harm, though when they pass into intensively grown crops - such as wheat or coffee - they can cause major crop failure. They're a fascinating group and very few people study or record them, so you can really make a difference if you get to know them and submit your records to your local biological records centre, such as Cofnod in North Wales.

Debbie kicked off with a presentation to introduce us to the world of rust fungi. The Romans even had a God, Robigus, of rust fungus, and a festival on 25 April each year when an animal would be sacrificed to appease Robigus and seek a successful harvest, free of wheat rust.

Over the previous few days, Debbie had collected rust fungi from lots of different host plants so that we could see the variety. Many are very common, but some are much rarer and qualify for the Red Data List for Wales, of which Debbie is a co-author.

Using the samples that she collected, Debbie showed us how to prepare a slide to examine the individual spores more closely. 

Some rust fungi go through as many as five stages in their life-cycle, and the spores vary in size and shape.

After lunch, we headed outside for a foray around the reserve. Us amateurs quickly realised that there are lots of things that cause discolouration of leaves, and only a few are rust fungi. We kept pointing out insect galls, leaf-miners, powdery mildews, and smuts (another type of fungus) to Debbie, but eventually we found our groove and recognised the raised streaks, bumps, cups and postules that indicate the different stages of rust fungi.

A hand-lens is crucial for identifying rust fungi in the field. In just over an hour, we found 15 different species, some of which were on different host plants, so making 19 records in total.

Debbie saved the best until last, as she refound Pucciniastrum agrimoniae on a patch of common agrimony near the pond-dipping area. This is one of the Red Data species for Wales, which Debbie found here last autumn, and so we have been careful to ensure we don't accidentally chop down the patch of agrimony on which it has made its home.

Thanks to Debbie for her time and expertise, and to all the participants who hopefully have gone away with a greater appreciation of these overlooked and under-recorded organisms. Next time you're out for a walk, find a bramble bush and look for reddish-purple coloured markings on the upperside of the leaves. Congratulations, you've almost certainly just seen a rust fungus.

We are working on a fungus list for Conwy reserve, but you can download lists of other groups of plants and animals from our website. Debbie will be running two more events this autumn: a Fungi Family Fun morning (for 5-10 year olds and their families) and a grassland waxcaps and fungi workshop, both on Saturday 28 October. Ring us on 01492 581025 to book your places.