ToME: the Tales of Maj'Eyal

So which skills actually work with the Fungus tree? As far as I understand it boosts any kind of regeneration effect but that doesn't appear to be true as skills like Bloodbath don't interact with it.

Any regeneration which gives you a little leaf icon on the effect bar, which is labeled "Regeneration", is compatible with Fungus.

Bloodbath gives you a different effect, which grants both Life and Stamina regeneration.