I reached Blackreach last night, and I found the first Crimson Nirnroot - apparently this is part of a quest that will give me a particular perk if I can find 30 of these Crimson Nirnroots. The perk gives me a 25% chance to create two of a given potion when I mix ingredients.
I'm not really interested in duplicate potions (I have far too many potions and ingredients already), but it would be helpful for raising levels if I got twice the Alchemy experience when this ability fires and I create 2 potions instead of 1. Is this the case? Or do I gain only the experience for creating the first potion?