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!
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.
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.
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://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.