Unknown algea... not your standard pest algea

[dockrat]

Does anyone have any idea what kinda algae this is ? i have looked in my 2 algae books with no luck i have also looked in the standard web pages for hichikers... It is quite slow growing and dose not go sexual, but you need to keep it pruned to keep it looking nice

thanks kris
http://www.canreef.com/photopost/dat...wn_algea_1.jpg