Growth On Bogwood?

[GUB]

I seem to have a small patch (about 1 inch diameter) growth of greyish-brown 'fluff' on one of my pieces of bogwood. I havent noticed it until today, suggesting it has grown reasonably quickly. Is this algae or fungus (or indeed something else). Should I take the bogwood out and treat the water, or is everything OK?

 

[The-Wolf]

IME it is quite common for "new" wood and goes on its own in a few weeks.