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Witches' Butter

Exidia sp.


Probably Exidia glandulosa - the visible parts look like drops of tar randomly sprayed on the bark of this tree. Upon closer inspection I realised they were black gelatinous lumps, of irregular or vaguely spherical shape, protruding through the bark and moss. These lumps measure anywhere between 2 to 5 cm across and tend to aggregate into larger gelatinous form. Underneath the dead bark (pics 1 to 3) I've found what looked like younger lumps, more roundish and translucent and grey. There were also some whitish mycelium there.


Seen on and under the bark of a broadleaved tree in a mixed forest (oak, beech and fir trees), on hills in a valley between Jura mountains and Geneva lake. The tree itself (probably a beech) looked dying, as the bark was falling down in large patches.


Difficult to differentiate the two members of Exidia genus: E. glandulosa is easy to confuse with E. nigricans; which is the reason I preferred to leave it at genus level.

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1 Comment

Ingrid3 8 months ago

really cool!

Zlatan Celebic
Spotted by
Zlatan Celebic

Grilly, Auvergne-Rhône-Alpes, France

Spotted on Jan 31, 2021
Submitted on Feb 3, 2021

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