These slime mould aethalia on a stump were a wonderful find — the cream colour and the brownish orange discolouration on the aethalia didn’t seem very Fuligo septica.

A Google Lens search suggested F. candida but not satisfied I checked out Bruce Ing’s handbook [1] where he describes the cortex of F. candida as being white and that it “is found on fallen bark and rotten wood in woodland and hothouse litter”.

But does white mean white or could cream be within the scope of white?

As an aside, in the handbook, Ing states that F. candida has the synonym of F. septica var. candida and that it is “maintained by many authors as a variety of F. septica“. I then discovered a paper by Thomas Hoppe [2] where the identification key lists candida as a variety of F. septica which appears to be confirmed by nomen.eumycetozoa.com [3] and Mycobank [4] – that candida is a variety of F. septica.

Danish Myxomycetes’ key to Fuligo [5] refers to peridial lime colour — do they mean the colour of the cortex? If so, they describe the peridial lime of F. septica var. candida as white to cream coloured.

https://www.mycodb.fr/fiche.php?genre=Fuligo&espece=intermedia&numphoto=2&source=list&filter=&numfiche=2927

The entry for F. candida at Mycoquébec [6] states that it has “a beautiful white colour which helps with it’s identification” but there are some photos that show some specimens as more cream coloured than white.

But if cream is not white then using Mycoquébec’s key to Fuligo we get directed to either F. septica — which typically has the classic yellow cortex — or Fuligo intermedia.

Referring back to Ing’s handbook, Fuligo intermedia is “often in small groups” (subgregarious) up to “3 cm in diameter and 1 cm tall, dirty white or pale grey” and “occasionally tinted with pale shades of brown, pink or yellow” — which these aethalia have — and is found “on dead wood, especially stumps”.

So, could this slime mould we spotted be Fuligo intermedia or is it F. septica var. candida or just a paler common F. septica ? In his handbook, Ing states that F. intermedia is rare but has been identified in Norfolk and that it is “a poorly defined species, or perhaps a mixture of several needing critical study”.

[1] The Myxomycetes of Britain and Ireland (2024 reprint of 2020 edition) – Bruce Ing
[2] Mycosphere Vol 8 Issue 10 2017 – https://www.mycosphere.org/pdf/MYCOSPHERE_8_10_17.pdf
[3] https://nomen.eumycetozoa.com/data/report.php?busca=fuligo&por=gensi&id=983&tipo=Btax
[4] https://www.mycobank.org/ – search for Fuligo candida
[5] http://www.myx.dk/dk/dkgenful.html
[6] https://www.mycoquebec.org/bas.php?tag=Fuligo+candida&iumq=750