Lichen (Graphis scripta)
Until I happened to be looking for a lichen I had seen in my reference book and stumbled across something called Graphis scripta I had always assumed that the black marks you often see on Silver Birch bark were just blemishes in the bark itself! How wrong I was.
These black marks or, indeed, a lichen that is common on smooth barked trees but it shows up best against the pale coloured silver birch.
Common across the country, as well as Dorset, it has a close cousin, Graphis elegans, and they are very hard to tell apart but I believe this to be scripta but if you think I am wrong please let me know!
Find out more about the nature of Dorset at my website www.natureofdorset.co.uk