Algae on wood identification

[dontbyteme]

Can anyone help to identify the type of algae (if it is?), the greyish clumps, that is growing on my driftwood? As opposed to hair algae that usually infest my moss and plants, these greyish algae always start growing from the driftwoods itself and grow even in unexpected places like the underside of my driftwood which is highly exposed to light.

These driftwoods have been in my tank for more than half a year and did not appear in the beginning when the tank was still maturing.

[barmby]

It is not algae , I had them before , it is some kind of bacteria I believe