Fungi Covered Staff Stacking?

[Krazl]

Does the click effect from Fungi Covered Staff stack with the regen line of druids/shamans?

The best I could find was an argument on allakhazam, some saying yes some saying no, with the people who claimed it stacked saying you had to have SoW in your first buff slot and regen/chloro/regrowth in the second - after which clicking would only remove the SoW.