Species of the Month - December 2012

Dice Lichen

Pertusaria pertusa

Often called the Pepper-pot Lichen but I think it looks more like a dice, with any number from 1-6, or sometimes even more, showing on its top face, and other numbers round the side.  This is a common lichen found on many kinds of trees, on both smooth and rough bark, and occasionally on rock too.  On the lnhg database we have 5 records on Ash, 3 on Oak, 2 each on Sycamore, Rowan and Birch, 1 each on Beech, Hazel, Alder and Willow and one on an unidentified tree.  This suggests it has a preference for trees with alkaline bark but will accept acid ones.  We have not yet recorded it on rock.

Pertusaria pertusa

The "fruits" or apothecia of this lichen are black and are immersed in the warts with just a small area of black showing like a small round dot.  There ae several of these per wart, though a minority of warts have only one.

Pertusaria pertusa

The area between the warts in the Dice Lichen can be white or pale grey or have a greenish tinge.

Pertusaria pertusa

Here is the Dice Lichen on Hazel surrounded by the fungus Stereum rugosum and various other lichens.

The species most likely to be confused with P pertusa is P hymenea, which has mostly one apothecium per wart though some warts may have two or three.  In P hymenea the visible part of each apothecium is much larger than in P pertusa and is often elongated.  There are good pictures of P hymenea at http://www.britishlichens.co.uk/species/Pertusaria%20hymenea%20large.jpg and http://www.habitas.org.uk/lichenireland/photo.asp?item=mjs00597

Please send in your Dice Lichen sightings using the form below.  If you are not sure of the identity of your lichen, 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 
Grid reference 
Host tree species (or other substrate e.g rock) 
Name of finder 
Your name (if different) 
Email (not needed if I already know it!) 
Any other details 


By filling in this form you agree that the information contained in this form may be collated and disseminated manually or electronically for environmental decision-making, education, research and other public benefit uses in accordance with the LNHG data access policy.  Your email address will not form part of the record and will not be passed on to anyone.

Carl Farmer
G Biological Records Manager

Sightings so far

15 Dec: we found some on Ash at Dunadd on our lnhg Saturday walk

21 Dec: I spotted some on Ash at Taynuilt

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

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