Orange Powder on Tree Trunk

What I think is an alga, possibly Trentepohlia sp., on the trunk of a (living) silver birch tree.  Although orange in colour, this is classed as a green alga (Chlorophyta), the chlorophyll green being masked by yellow and red carotenoids.  

Photo taken in the Wilderness, Whiteknights Park, Reading University grounds, Reading, UK, on 2010-04-13.

Comments

[Sue White]

Thanks for that. It caught my attention on that very tree! I've also seen it on ash trees in Sussex and the Chilterns.

[Amanda]

I think the same stuff causes a rather splendid effect at Snelsmore Common near Newbury. Thank you for the information, which I have duly credited to you in my own post.

http://amanda-bates-artist.blogspot.com/2014/06/gold-and-silver-birch-snelsmore-common.html