Eugenol is the main element in clove essential oil – and also found in other plants, including allspice, bay, cinnamon leaf, patchouli and pimento. (Although eugenol is also produced synthetically, nowadays.) When perfumers add eugenol to a fragrance’s construction, we may actually detect a hint of spicy carnation in there.
Unusually for a perfume ingredient you’ll quite often see it listed on the back of the carton which your fragrance bottle is packaged in: eugenol’s use is now restricted in perfumery, as it’s been known to cause allergies in some people, so it must be mentioned on perfume ingredients lists to alert them.