Gavin Sowry
Garden Railroader and Raconteur
It's moss, growing, in part, over a boulder. Common name for it is New Zealand (how surprising) Moss, somewhat similar to Spanish Moss apparently.
JR did post the botanical name for this on this very thread.... hang on a sec, make that a minute or three, while I find it for you.
Still there Mick? Of course you are (silly question, sorry). Check out Post#386 and 387.