Plastic fantastic

 I mentioned in my last post that I had plans to investigate a sheet of black plastic that I had acquired while helping friends move house. Here it is again with a ruler for scale:

Looking at the cover of lichens, there are three kinds.  The flat round patches are crustose lichens. Here is one in detail:

Lecidella elaeochroma - a crustose lichen

I had seen this lichen before on trees but it looked quite different on  the plastic.  Just above it on the photos is a leafy or foliose lichen.  This is a tiny little Physcia species. There are other foliose lichens on the plastic that form leafy rosettes. Finally, the lichens that stick up like small bushes are called fruticose lichens.

Lecidella elaeochroma has the handy property of glowing bright orange in UV light which is a big help with identification. Here is a picture of it on an elm trunk.

Lecidella elaeochroma glowing orange under UV on an elm trunk.

Confusingly, on the plastic it glowed yellow rather than orange which made me doubt whether it was Lecidella elaeochroma, but further investigation confirmed it was. I also got confirmation from a lichen expert called Brian Coppins who was visiting me. A lovely man who is very generous with his time and expertise.

He took a look at my piece of black plastic and immediately pointed out a lichenicolous fungus (i.e. a fungus that grows on lichen) with the unpronounceable name of Zyzygomyces physciacearum. 

 Zyzygomyces physciacearum on Physcia

The lichenicolous fungus (let's just say LF) takes up home  on the lichen of its choice and proceeds to change how the lichen grows, producing lumps and bumps that spread the fungus.

The warty lumps and bumps of the LF

I've not investigated this one yet, but I did look more closely on the other lichens and found some more LFs.  One produced a big (well, big for a lichen!) 4mm balloon like growth called a gall on a different lichen.  

I cut it open and it was hollow inside.

The white strands are hyphae, the name for strands of fungus.  The black dots are part of the LF where it can produce spores.  Unfortunately, this one had not produced enough spores for me to identify it.

I had more luck with a different LF where the circular black bits had made some spores.

The spores are inside tube-like sacs called asci with 8 spores in each.  The picture looks blue because I used fountain pen ink to stain the sample which makes it easier to see.  There was enough detail to identify this LF as Lichenochora galligena and it was on Physcia aipoliae.  Thanks go to Brian Coppins for confirming the ID.

These LF are rather tricky and I think I will go back to "normal" lichens for the time being as there is plenty for me to learn there.