Monday, 9 October 2017

Mycena pearsoniana: Not a first for Suffolk

We didn't have ideal conditions for our fungus forays around Flatford Mill at the weekend. An extended period with little rain had left the ground very dry and some of Geoffrey Kibby's usual hunting grounds were almost entirely devoid of mushrooms.

But you can see too many mushrooms, and the advantage of sub-optimal conditions is that it gives you the chance to examine what fungi you do find in detail. It can also cause you to pay attention to things you might have otherwise passed by.

And so it was with this pinky-purplish mushroom, not much more than 1cm across, which was spotted growing in tussocky, scrubby grass...


... right about here (TM079330), on the thin strip of grassland between the footpath and the eastern side of the pond:


As well as its distinctive colour, this mushroom had a couple of other distinctive features: a stripey ('striate') margin to the cap; and decurrent gills which had clearly once run a little way down the stem, although now broken away.


Geoffrey provisionally ID'd it as Mycena pearsoniana, a species he has only come across a handful of times in 53 years of foraying. Which had the effect of making this small, rather dull-looking mushroom suddenly VERY EXCITING.

Once back in the classroom, we compared our find with the description of M. pearsoniana on the excellent 'Mycenas of Northern Europe' site, here. The macro-features all seemed to fit.

With respect to micro-features, the description talks about cheilocystidia "forming a sterile band" which I think is what I was looking at here, on the gill edge.


The cheilocystidia look like this, which I think puts them in the region of 'subfusiform' (albeit some of them look like they're verging on 'utriform').



The spores are fiendishly difficult to see, and impossible to photograph, but I think I've succeeded in measuring a few and they fit within the range for M. pearsoniana: 6 - 9 microns. There is no colour change in Melzer's Reagent.

All these micro-features seem like a decent match for M. pearsoniana. Hurrah!

Based on an initial look at records on the FRDBI database, we thought this could be a first record for Suffolk. However, on a second look I see there is one record for East Suffolk (VC: 25), collected by A. Henrici and identified by S. E. Wells from 2009. Still, a real rarity!

After my casual mention of a possible first for Suffolk on my last blog (here) I was contacted by Neil Mahler, the County Fungus Recorder, requesting details. In an exchange of emails, Neil very helpfully explained some of the background to fungus recording in Suffolk. Two mycologists called Martin & Pam Ellis produced a county checklist in 1988 (available on the Suffolk Biodiversity Information Service website, here). The checklist contains three records of M. pearsoniana: one found by the Ellis's from nearby Dunwich Forest; one from East Bergholt near Flatford by "A. J. Parker-Rhodes and his students"; and one from Staverton Thicks on a BMS foray with the aforementioned mycologists all present. The East Bergholt collection was recorded at Fishpond Wood, about 2 km from where we found it!

I wonder if there is a typo in the rendition of "A. J. Parker-Rhodes" name in the back of the Suffolk checklist, as the introduction talks about a Dr A. F. Parker-Rhodes who "organised fungus study weeks at the Flatford Mill Field Study Centre, foraying extensively in the surrounding area". Wikipedia relates that Arthur Frederick Parker-Rhodes (21 November 1914 – 2 March 1987) tutored a course on fungi at Flatford Mill for nearly 30 years.

Unfortunately the Suffolk checklist doesn't include dates for the records, but it must have been more than thirty years ago that Dr A. F. Parker-Rhodes was tramping around Flatford Mill with his students in tow, and found M. pearsoniana.

So, not a first for Suffolk. But a rather nice reminder that we walk in the footsteps of mycologists who have gone before us. Sometimes quite literally.

With very many thanks to Geoffrey Kibby for identifying this little mycena, and to Neil Mahler for putting this observation into context.

Specimen retained (Ref. CMB00002) and record to be submitted to the FRDBI in due course.

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