21 January 2018

Snakeskin Brownie

Snakeskin Brownie (Hypholoma marginatum, also known as Hypholoma dispersum) is a fairly common toadstool in local Sitka Spruce plantations although it is generally uncommon in Europe as a whole. It gets its fabulous common name from the characteristic snakeskin pattern on the stipe. Given its preferred habitat, often growing on buried wood litter or wood debris among mosses, and its characteristic morphology, it is not usually difficult to identify.
In the autumn of 2016 Hilary and I came across 3 populations of a fairly distinctive toadstool in Neath Port Talbot and Rhondda Cynon Taff composed of fruiting bodies clustered in large numbers on conifer wood debris or wood chips. All were in conifer plantations at the side of forest roads but outside the forest. A photograph of part of one population growing on Sitka wood chips in the Maerdy Plantation (RCT) is shown below.

I couldn't identify this species at the time, but after microscopic examination of specimens I was convinced that it was something in the Strophariacea, a large family of brown-spored species that includes a number of well known genera such as Stropharia, PsilocybeHypholoma, Pholiota and Kuehneromyces. Given the number of species new to Britain that have been found growing on wood mulch in the last few decades, I was excited. Eventually I contacted Martyn Ainsworth at Kew who suggested that the only way to resolve this was to look at the DNA profile of the specimens, so I sent him some photos plus dry specimens from two of the populations and a spore print. I was delighted to hear from Martyn about 2 weeks ago when he informed me that the DNA profiles indicated that the specimens were actually Snakeskin Brownie - the material has now been accessioned into the Kew collection and DNA database for future reference.
I didn't even consider Snakeskin Brownie at the time, mainly because I was so used to seeing it in its characteristic form, as shown in the upper photograph. Looking at both photographs now, I can see a resemblance that can be accommodated in terms of the enormous morphological plasticity that fungal fruiting bodies often exhibit. However, if you flick through a gallery of photographs of species in the Strophariaceae you will understand the dilemma. This also illustrates how unsafe it can be to identify some fungi from photographs, something that Martyn constantly reminds people about.
My thanks to Martyn Ainsworth and his team at Kew for resolving this.


Barry Stewart said...

Great detective work Charles - you are the Sherlock Holmes of South Wales' conifer forests!

Charles Hipkin said...