Oakmoss

Oakmoss is just that -- a type of lichen that grows on, get this, certain oak trees.  It's used in perfumery and, ohh, does it smell amazing.  Very sweet and fresh and woodsy and lingering.  Smells like the outdoors on a good day -- what could propel you to fish out your hiking boots and hit the trail; remind you what it's like to be surrounded just by trees.  Oakmoss is a "base note" in a lot of  perfumes; used by everyone from the ancient Egyptians to Coty.  There was an uproar over Oakmoss cause it could be sensitizing to some people.  Considering that the concept of essential oils/absolutes is that they're extremely concentrated, it's not much of a surprise that some skin can be sensitive at that level of concentration.  Unfortunate for those sensitized but still a wonderful smell for the rest of us.