Take a little orange blossom, some oil from the leaves and stems of a bitter orange tree and I'm guessing oil from the zest? of an orange---and mix it up. Enhance with whatever Hiram Green used--perhaps a little Birchwood, a hint of Ambergris or Civet, something. Then stand back, because you've just made orange heaven. I love, love this perfume. Petitgrain elevates the orange blossom, which turns around and softens the Petitgrain. The result is intoxicating. A beautiful idea, very well-executed. For me, FB mandatory.
Edit: FB having arrived, I over sprayed and discovered that too much of this fragrance becomes less than lovely. Apply it with restraint to get the glorious.