Shirley Estate, Carrickmacross

I joined the Monaghan field trip to this huge estate for a few hours, and was amazed by the variety of rich and unusual habitats. The estate is on limestone (yay!), and at one point we were in what seems to be a 'doline', where a stream had run underground, forming a cave which had then collapsed, leaving a kind of amphitheatre, with a smooth limestone wall to one side and trees growing round the other three sides.

Here's a shot looking down into the doline with the sheer limestone surface at the top of the image:

Looking down into the doline

I was 'doing' hoverflies and leaf-miners but, as usual, I was taking shots of whatever looked interesting.

Whilst checking for leaf-miners, I found this blotch on Horse Chestnut:

Guignardia aescula on Horse Chestnut

At first, I couldn't make up my mind whether it was a mine or a fungus, but when I looked under a hand lens, I could see the fruitbodies of a minute fungus. It's Guignardia aesculi.

There were a few small areas of very marshy ground with associated sedges and other plants and insects. This is Bladder Sedge, which formed large drifts of densely-packed leaves:

Bladder Sedge

New to my species list.

This was my first clue that I was on limestone:

Cuckoo Pint

Cuckoo Pint (or Lords and Ladies) is a beautiful plant that I have only ever seen on lime.

We found this Great Diving Beetle as we crossed a field between bogs. There are a number of very similar species, all of them vicious carnivores. Whilst this one was being held for identification, I heard the immortal words from the identifier: "Hey, ouch, let me go!"

Great Diving Beetle - Dysticus marginalis

New to my species list.

I have noticed a few fungi peeping up on lawns and grassy areas, but this is the first 'mushroom' that I have seen this year:

Omphalina pyxidata

Omphalina is a very interesting genus of fungi, but in order to explain this, I need to take a few steps back:

Lichens are a composite organism formed from a combination of a fungus and one or more 'partners'. The partners are usually algae, but can sometimes be cyanobacteria. This association is usually described as a symbiotic relationship, but I'm having none of that: the fungi can't live alone, but the alga can, so I see this more as a parasitisation of the alga by the dominant fungus. The fungus gains the benefits of a photosynthetic partner, but what does the alga receive?

The fruitbodies of lichens are always purely fungal, and can often resemble tiny mushrooms (which they actually are), so we can have boundary species which appear to be fungi, but can actually be lichens. Omphalina sp. take this a step further: they can happily live their own lives like any other mushroom, but in times of stress, they can capture algae to supplement their food resources. So some Omphalinas are part-time lichens.

New to my species list.