Sycamore tarspot

09 Friday Sep 2022

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British fungi, fungus on Sycamore leaves, Rhytisma acerinum, sycamore, Sycamore tarspot

As the South East Wales Biodiversity Records Centre has only 400 records of the very easily identifiable Sycamore tarspot (Rhytisma acerinum) in its database, SEWBReC staff have chosen this fungus to be the September species of the month to inspire as many people as possible to find and record this fungus. Using the Welsh records database Aderyn, it’s possible to see where people have recorded Sycamore tarspot and, more importantly for this exercise, where they haven’t. I know this fungus is very common in my local area, yet there are few records.

So, I’m making it my mission during my walks this month to find and record Sycamore tarspot in as many 1-km squares as possible. I got off to a good start on Wednesday, with records logged in four new squares. It will be interesting to see how many more I can get, and to see how many records other people manage to find over the next few weeks. I’m picking the map will change dramatically by 30 September.

220909 sycamore tarspot

Fungi finger prints

06 Sunday Mar 2016

Posted by sconzani in fungi, nature, nature photography, trees

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Tags

fungus, Rhytisma acerinum, sulphur dioxide air pollution, sycamore, Tar spot

Well, they look a bit like finger prints to me – or, perhaps, the wax seals people used to stamp on their communications and documents. But no! These are, in fact, the signs of Tar spot, a disease that most often affects sycamore trees but can also occur in other species of acer, and is caused by the fungus Rhytisma acerinum.

Rhytisma acerinum Sycamore Tarspot (1)

The spots start out yellow in the springtime, then eventually morph into the slightly raised bumpy black spots you can see in my photos. Although they look a little ugly, the spots don’t affect the health of the trees – they merely cause the leaves to drop a little earlier than normal in the autumn.

Though you might not like the look of them, there is one big benefit to seeing these spots on your sycamore tree: as the fungus is particularly sensitive to sulphur dioxide air pollution, its presence indicates your air is relatively clean and healthy.

Rhytisma acerinum Sycamore Tarspot (4)