Resource for identifying mushrooms?

[ben01]

Is there a good website with a guide to id'ing the different sorts of mushrooms? I don't mean types of named exotics but something that show the difference between ricordia, rhodactis and so on. I want to be able to go into an LFS and know what I am looking at.

Thanks.

 

[Apercula]

At a quick glance this looks pretty good. A lot of the mushrooms available are identifiable to genus but rarely species level.

http://animal-world.com/Aquarium-Coral-Reefs/Mushroom-Coral-Information