Plant ID, all long filaments

[outofwater]

Hi everyone,
When I was setting up my tank I saw this floating plant at the LFS and liked how it looked. The guy couldn't tell me what it was.

It came with a fake plastic ludwigia that works as an "anchor" for it.

I'd like to know what it is, I actually haven't seen it in any of the "big chain" stores around me.

Thanks in advance

 

[ember04]

It’s Java moss but a big ball of it

 

[Colin_T]

Java Moss with lots of dead bits in it. The plant should be green, the brown bits are dead or covered in something gross.