Sulphur Tuft – Hypholoma fasciculare

Fungi represent a challenge when it comes to natural compasses. We can use them to make maps quite easily, but they don’t photosynthesise, so their aloof relationship with light means that direction is not so easy.

My thanks to regular correspondent and torch-carrier for natural navigation in FranceAlban Cambe – for sending in this intriguing observation. Over to Alban:


I think, after several sightings, that we can rely on a fungus to deduce
the directions.

This autumn, I’ve been foraging for mushrooms a lot and got to identify
new species I didn’t know.

Among them, Hypholoma fasciculare (the Sulphur Tuft) which grows on stumps.

Sulphur tuft on the south side
Compared to the north side

I noticed several times that the fruiting bodies grew differently on
these stumps in my local wood : they seem to develop faster and bigger
on the sunny side and stay small on the shady side.

Furthermore, they look much orange on the northern side than on the
southern side where they appear to be more bright yellow.

The only explanation I can come with is that fungi rely on warmth for their metabolic activity. Therefore, the sunnier side of the stump should be an area of better growth. Especially given the colour of the wood.

I also noticed these fungi on some fallen trees (especially oaks) with more fruiting bodies on the sunnier side.

BUT ! (it couldn’t be as easy)

It looks like no two mushrooms have the same habits. I did not do enough observations but it seems that the Hoof fungus (Fomes fomentarius) grows more on the shady side of trees in my local wood… I will do some more research… As with Cramp Balls / King Alfred’s Cakes (Daldinia concentrica) which seems to prefer shade (but grows on dry wood).

Anyways, I feel Hypholoma are reliable as they grow nearly everywhere and demonstrate pretty much always the same behaviour.


Congratulations Alban, a pioneering observation and one that is new to me. Has anyone else spotted this? Get in touch if you have.

Read more of Alban’s discoveries here.

With knife for scale

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The Strange Map Made by Parasol Fungi

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