Smell Chanel No 19, and the first thing you will notice is the intensely green, somewhat earthy note. That effect is created by galbanum, a natural resin collected from several species of flowering Ferula plants, which are native to Iran and the Middle East. The oil is steam-distilled and has a very powerful, green, woody-resinous odor, reminiscent of sliced green peppers and hyacinth leaves. Its verdant notes are immediately apparent in fragrances, while the balsamic-woody facets come through as the composition dries down. Galbanum is a traditional note to give a natural green effect to floral accords like hyacinth, gardenia, narcissus, iris and violet. While on its own, galbanum has quite a brash, roughewn character, it lends a beautiful, natural green effect.
Green compositions like like Balmain Vent Vert, Chanel No 19, Guerlain Chamade, Estée Lauder Aliage, and dry woods like Robert Piguet Bandit and Aramis are inconceivable without the green vibrancy of galbanum. Also, there is a fair amount of this material in Serge Lutens Iris Silver Mist, by Kilian Love & Tears, Atelier Cologne Grand Néroli, and Guerlain La Petite Robe Noire Modèle 2, among the more recent launches.
A side note on galbanum, fragrance and politics. When Chanel No 19 was created in 1971, it was formulated with a superb grade of Iranian galbanum oil, which was sourced especially for it. However, when the Iranian Revolution broke out in 1979, the oil became unavailable. No 19 had to be reformulated, which was accomplished with much difficulty, because the original galbanum oil was of a particularly fine, rare caliber.
From a culinary perspective, the plant producing galbanum is related to the one producing asafoetida, an extremely pungent gum resin used in Indian cooking. These two gums, galbanum and asafoetida, share several similar components, which are responsible for their pungency and unique green character.
Photo of galbanum from anthemis.nl.