Le Labo, in their ongoing conflation of ingredient lists and titles, have made a great contribution to the reinvention of the chypre. It's easy to misunderstand the chypre, focussing on the surface or its list of ingredients (bergamot, oakmoss, labdanum) rather than its complexity and balanced tension.
Trying to create a new chypre by replacing banned ingredients with less oppressive ones that smell the same is a strategy that aromachemical producers would love to employ. They would love to create the new captive molecule that re-creates all the beauty of oakmoss without any of its drawbacks. Le Labo take a more interesting approach. Ylang 49 doesn't attempt to fill in the missing pieces of the original formula. It tinkers with the dynamic qualities of a chypre and recreates the sensibility with different constituent parts. It has an aggressive opening on par with the haughty start of a stark chypre. It subverts the middle-notes a bit. A tropical twist, a sort of ylang/gardenia note, allows humid florals to coexist with a dry woodiness that eventually winds up a cigarette-voiced basenote on the patchouli/benzoin axis. Ylang 49 retains the scratchy, purring quality of a floral chypre and keeps all the peculiarities and unresolved tensions I associate with a floral chypre.
The floral chypre informed classical perfumery's working proposition that flowers are equally fetching and ferocious. Historically, beginning somewhere in the late 1980s, the credo of the fruity floral crushed floral complexity in a stampede. This credo holds that flowers should merely be simple, loud and match the sickly punch of fruity half of the fru-flo. Ylang 49, chypre or not, reminds us of the power of the flower.