Melma del Salone di Sangue

A permanent that’s both black and green will allow both abilities to trigger (as will separate black permanents and green permanents, of course).

The “intervening ‘if’ clause” means that (1) the ability won’t trigger at all unless you control a permanent of the specified color, and (2) the ability will do nothing unless you control a permanent of the specified color at the time it resolves.