Mistletoe

From a distance I thought there were lots of bird's nests in this tree, but when I got closer I realised it is, in fact, mistletoe.

You will, of course, all know that mistletoe is an obligate stem parasite which means it cannot complete its life cycle without the presence of a host ( i.e. is obligate), and it attaches itself to the stem of the host (i.e. the tree).
I bet this lot would be worth a bit around Xmas!