I was looking in wikipedia for the term "indole" and I found some interesting information:
"Indole is an aromatic heterocyclic organic compound (...) Indole is a solid at room temperature. Indole can be produced by bacteria as a degradation product of the amino acid tryptophan. It occurs naturally in human feces and has an intense fecal odor. At very low concentrations, however, it has a flowery smell, and is a constituent of many flower scents (such as orange blossoms) and perfumes. It also occurs in coal tar.
(...) Natural jasmine oil, used in the perfume industry, contains around 2.5% of indole. Since 1 kilogram of the natural oil requires processing several million jasmine blossoms and costs around $10,000, indole (among other things) is used in the manufacture of synthetic jasmine oil (which costs around $10/kg)."
Yes, orange blossoms, gardenias, and tuberose are also indolic flowers and depending on the concentration, can lend voluptuous and sultry notes to a perfume.
But what about champaca flower, neroli, magnolia, ylang ylang or lotus?
I found some answers here too:http://www.thegoodscentscompany.com/data/rw1006511.html
See on the right the column "Natural occurrence in" :
bergamot oil @ 0.000-0.009%
absolute @ 2.90%
champaca concrete @ 4.00%
couroupita guianensis aubl. flower oil brazil @ 0.20%
jasmin absolute concrete egypt @ 3.84%
jasmin absolute concrete india @ 1.07-1.85%
jasmin absolute concrete italy @ 1.39%
jasmin oil italy @ 4.21%
lecythis usitata miers. var. paraensis (ducke) r. kunth. flower oil brazil @ 0.40%
mikan peel oil @ trace%narcissus
absolute @ 1.51%
narcissus absolute @ 6.30%neroli
neroli oil CO2 extract @ 0.45%
absolute morocco @ 2.6-9.9%
orangeflower water absolute @ 0.0-3.2%
petitgrain combava oil @ trace%
thyme oil wild or creeping france @ 0.09%
oil CO2 extract @ 0.13%