There’s a fungus on the Town Hall Clock!

If you’ve read my latest post you would know that I am a regular participant of #wildflowerhour. During last week’s Wildflower Hour there were predictably more photos due to the increase in flowering plants as spring progresses. Among these flowering plants was the easy-to-overlook Moschatel (Adoxa moschatellina), which I had never recorded before.

So last week I set out with a picture of Moschatel in my mind so that if I did come across the species I would recognise it. Yesterday I visited Pulborough Brooks RSPB reserve in West Sussex and I did both of those things: I came across a couple of large patches and I recognised it!

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The flower head. You can see that it is cube-shaped, which is what lead to the alternative vernacular name of ‘Town Hall Clock’.

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The whole plant

As you can see from the above photographs, Moschatel is not a hard plant to miss. Its flower heads are only slightly lighter than the leaves and therefore not easy to spot when they are lined up against the foliage of a woodland floor. To be honest, I was quite pleased with myself for managing to spot this indistinctive plant!

However once I had a closer look, there was more to see. One particular patch was very heavily infected with what appeared to be the fungus Puccinia albescens, which covered the leaves, stem and flowers of several plants. This species is a rust fungus, which is a type of fungus that usually parasitises wildflowers and other small plants. There is an incredible diversity of host plants within the 7000 species of rust fungi as most plants are only infected by a single species.

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The close-up photograph above shows the pustules of the rust fungus, which is just one part of the complex life-cycle of rust fungi. These pustules erupt at this time of year and produce uredospores which are carried on the wind to new plants of the same species to infect.

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Telia

Also present alongside these pustules are what I believe to be the telia of the same species. These telia – the dark, round spots – are produced in the autumn in most species and would have overwintered. The telia produce teliospores, which are another method the fungus uses to spread as they disperse to find more plants of the same species to infect, just as the uredospores do.

The life-cycle of rust fungi is very complex and here I have explained it only briefly – different species of rust fungi can have different life-cycles and some infect two completely unrelated species during their life-cycle. These multi-host fungi are known as heteroecious fungi and one host plant is infected by the uredospores and the other is infected by teliospores. As Puccinia albescens is not heteroecious (and is autoecious), its life-cycle can be completed on just a single host species – Moschatel – and the single host species is infected by both the uredospores and the teliospores. Some good websites to visit for more information on the life-cycle of rust fungi are:

http://www.biologydiscussion.com/fungi/life-cycle-and-the-spore-stage-of-rust-fungi-fungi/64083

http://website.nbm-mnb.ca/mycologywebpages/NaturalHistoryOfFungi/Pucciniales.html – this one includes a lot of information, however it also contains a lot of scientific jargon and complicated vocabulary.

Not always straightforward

During my Garden Bioblitz of the the 6th June, I found a moth case on a cotoneaster leaf. I tried to identify it by using this webpage and I thought it looked most like Coleophora trigeminella. I was very excited by this as the species hasn’t been recorded on Cotoneaster in the UK before, only in Europe. Could I have discovered a new foodplant for this species in Britain?

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I emailed the Surrey moth recorder, Mr Graham Collins, with news of my finds. I asked him whether it was likely to be Coleophora trigeminella or something else. He kindly responded saying that he didn’t think that the larval case belonged to this species but Coleophora serratella which is ‘probably the commonest species of British Coleophorid’ according to the UK Moths website. I was quite disappointed!

However, why was it on a cotoneaster leaf? The larvae usually feed on hazel, birch, elm or alder. It is most likely that the larvae fell from the foodplant (there is a birch tree straight above the cotoneaster) on to the leaf where it formed the case, or the larvae wandered off the leaf looking for a better place to create its case.

When I returned to the same leaf nearly a fortnight later, on the 18th June, I was given a huge surprise. The adult moth had emerged from the case overnight and was resting parallel to the case! It was so fresh in fact that the antennae were not resting forward in the typical coleophorid fashion but running backwards along the body! I sent this photo to Mr Collins.

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I thought that it was too light for Coleophora serratella and the ochre colour matched Coleophora trigeminella. Could I have found a species of moth that hasn’t been seen in Surrey for nearly half a century? Unfortunately that was not to be the case. Mr Collins responded writing that he now thought that the moth is either Coleophora flavipennella or Coleophora lutipennella. The larval stages of both of these moths feed on oak leaves, which makes sense as there are several large oak trees which also have branches above the cotoneaster bush. The larva probably fell from the leaves.

However, it is not possible to separate moths of those species without examination of the genitalia. For this I sent the moths off to Mr Collins by post and he kindly looked at them under the microscope. The genitalia point to Coleophora flavipennella, which I think might be the least common of the pair although I am not certain. The genitalia of C. flavipennella look like this:

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Compared to the genitalia of C. lutipennella:

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There is quite a lot of difference! This is a new species for me and I hope this blog post shows that often identification is not that straightforward.

(genitalia photos from http://www.mothdissection.co.uk)