Lachnellula - sorted!

So I took myself back to yesterday's larch and failed to find the tiny fungi on dead twigs for maybe fifteen minutes, before finding them in a closed up, even tinier state. Phew, maybe a third of a millimetre diameter, I would never have found them if I didn't already know they were there.

Back indoors I sprayed them with water, watched them open to their full size (approx 0.6mm across) and made a fungal squash. Whacking the slide beneath the compound microscope I was relieved to see spores. I'd already found a key to the entire genus, so unless they were new to science I'd nail the ID. 

Just a quick reminder of what they look like in situ, this pic from yesterday

It's the miniscule little 'cup' on a dead Larix twig. Today they were closed up and all but invisible

And here is a truly stunning image showing the spores in all their wondrous glory

Whoever said mycology isn't exciting?

I know they aren't much to look at, but there are clues that lead us to a specific identification. Firstly, the Worldwide Key to Lachunellula is amazing and can be viewed by clicking here. By working through the species one by one, I narrowed it down to just a handful that occur on Larch. Of those, one is found only in Russia, another occurs at high altitude in The Alps and other mountainous regions, helpfully they all had diagrams of the spores. Lacking both the required chemicals and a graticule for measuring the spore size, I basically picture matched my spores with those that occur on Larix and came to an ID. 

In the end it was a head to head between just two species, here are their spore shape

The main differences are that L.occidentalis has obtusely rounded ends to the spores whereas L.wilkommii has one end usually more acute. Subtle, yeah I agree. The other (rather helpful) difference is that one tends to occur on resinous cankers as a parasite and has an apothecia diameter of 3-6mm. The other is saproxylic on dead bark and has an apothecia diameter of 0.5-4.0mm. Oh right, that'll be my one then! And the answer is.... Lachnelulla occidentalis, just as I suspected yesterday. Nice to confirm though and seemingly 'new' to NW Scotland. 

Distribution of "Larch Disco" according to NBN (there's also a record from Shetland)

Talking of apothecia, here's a patch of Tree Lungwort that caught my eye. Apparently it only uncommonly produces apothecia, it seems that nobody told the Uig Wood population!