Fragrance

It would be helpful if someone would invent 'scratch and sniff' for the internet but alas that hasn't happened yet. 

The volatile organic compounds emitted by the cup (corona) and petals (perianth) of flowers evolved to attract pollinators of many sorts, from flies and bees to butterflies and moths. The genus Narcissus produces hundreds of compounds, which vary widely from species to species as well as within a wild specie's populations. Not only do these compounds attract pollinators but many have antimicrobial properties, contributing to the overall health of the plant.

In tazettas (N. tazetta and its hybrids), around ten or so floral compounds form the base “scent profile” and comprise the majority of volatiles released. [The fragrance profile of yellow tazettas being markedly different than that of the white-orange tazettas.] But it is the array of lesser and trace compounds that provide the nuance, such as those compounds found in lemon, rose, cinnamon, eucalyptus and pine. Paperwhites (N. papyraceus and its hybrids) have their own base scent chemical profile. The compounds of creosol (primarily) and indole (secondarily), which help give paperwhites their “scent,” turn out to be excellent pollinator attractants. Interestingly, the genus Narcissus is noted for having higher levels of indole than most flowers.

The production of these chemicals is genetically determined and inextricably linked to the morphologies of the corona and perianth. Changes in floret form through pollination (by insect or hybridizer) determine what chemical pathways are retained or lost in the progeny. Thus, flowers that look similar can actually “smell” very differently, depending on their specific species ancestors and the vagaries of hybridizing.

With hybrid tazettas, the base cross for many cultivars was a tazetta with a paperwhite. In general, crossing plants from these species groups seems to have greatly impacted the volatile chemical production in the progeny - namely, they cancel each other out. Thus, the majority of tazettas in the collection have only a light fragrance. 

Happily, occasionally a complex of chemicals was created rather than lost, producing a lovely fragrance. In some plants in the collection, the general sweet scent profile of the N. tazetta lineage was retained. In others, it was the amplification of secondary or trace compounds, creating an unexpected fragrance. It’s hard not to suspect that a number of otherwise pedestrian flowers made it into commerce based specifically on their distinct fragrances.