Species of the Month - January 2013

Willow Jelly Button & Birch Jelly Button

    Exidia recisa                 Exidia repanda

These are small jelly fungi about 1-2 cm across which are found on willow and birch twigs respectively, usually in the winter months.  January is probably the peak month for seeing them.  They are invisible after a spell of dry weather as they shrink to a thin film over the twig, but they swell up again as soon as it rains and remain that way for some time afterwards.

Exidia recisa   Exidia recisa

The pictures above show Willow Jelly Button, and those below are of Birch Jelly Button.  Both species seem quite common in our area compared to the rest of the country, or perhaps it's just that they're more visible here because of all the rain we get.  The Birch Jelly Button tends to have a flatter fruitbody while the Willow one often hangs down from the twig, but they can be safely told apart by their host tree alone.  There are no microscopic differences between them.
 

Exidia repanda   Exidia repanda

These fungi usually grow on dead twigs attached to live trees.  They break down the wood of the twig and feed on it.  Thin dead twigs high up in a tree dry out very quickly which is why the fungi have developed the ability to swell up and store water whenever they get the chance.  They can sometimes also be found on fallen twigs on the ground underneath the tree.
 

Exidia repanda


Please send in your Jelly Button sightings using the form below.  If you are not sure of the identity of your fungus, please send a photo to sightings@lnhg.org.uk, or put one on the LORN forum and let me know it is there.
 

Date of sighting 
Location 
Grid reference 
Host tree species 
Name of finder 
Your name (if different) 
Email (not needed if I already know it!) 
Any other details, e.g amount, habitat   


 

By filling in this form you consent to your record being passed on to the appropriate recording scheme.  Your email address will not form part of the record and will not be passed on to anyone.

Carl Farmer
SNH
G Biological Records Manager


Sightings so far

4 Jan: Chris Irvine found both species near Kinlochleven.

9 Jan: I found Willow Jelly Button at Inverawe, on what appeared to be Grey x Eared Willow

10 Jan: I found Willow Jelly Button on Grey Willow at Airds Bay, photo below

Exidia recisa


12 Jan: Birch Jelly Button found at Ardsheal by Jan Hamilton, Jan's photo below

Exidia repanda
 

These last two photos clearly show how the Willow Buttons are droopy while the Birch ones are more button-like.

14 Jan: Robert Macpherson found Willow Button on Eared Willow, and Birch Button on Downy Birch, both at Ganavan.

20 Jan: After a spell of dry weather, Jan went back to the site where she took the above photo, and managed to locate the buttons in their dried-out form.  These are almost impossible to spot unless you know where they are.
 
Exidia repanda   Exidia repanda

The one on the left has not dried out completely but on the right you can see how they eventually reduce to a dark skin over the twig.  Even though Jan knew where they were, she thought at first that they had all disappeared.

 

Note you can still send in records for past species of the month.  Here is the list of species we've had so far:

Dec 2012 - Dice Lichen
Nov 2012 - Feathered Thorn
Oct 2012 - Dryad's Saddle
Sep 2012 - Tawny Grisette
Aug 2012 - Forest Bug
Jul 2012 - Grayling
Jun 2012 - Greater and Lesser Butterfly Orchids
May 2012 - Small Copper
Apr 2012 - Green Tiger Beetle
Mar 2012 - March Moth
Feb 2012 - Barren Strawberry
Jan 2012 - Brambling
Dec 2011 - Red Squirrel
Nov 2011 - Hazel Gloves
Oct 2011 - Small Tortoiseshell
Sep 2011 - Fly Agaric
Aug 2011 - Grass of Parnassus
Jul 2011 - Golden-ringed Dragonfly
Jun 2011 - 7-spot Ladybird
May 2011 - Green Hairstreak
Apr 2011 - Townhall Clock

Mar 2011 - Frogspawn

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All photos and other content copyright Carl Farmer except where stated