The sulphur tuft fungus (Hypholoma fasciculare) must be a familiar sight to anyone walking in the woods in autumn. It has to be one of our most common fungi as it thrives on tree stumps. It grows in dense tufts or clumps and it is visible all year round. The yellowish cap can vary in size from a little as 2cm up to nearly 6cm and they start out convex in shape, then flatten out and eventually have a sort of Dutchman's cap appearance so plenty of variety to confuse the unwary like me!
Certainly not edible and best left alone.