The scent produced by plants serves two purposes: it attracts pollinators and deters organisms which pose a threat. For animals, the scent is a promise of nutritious nectar. Pollen carried by the hungry visitors enables plant reproduction. The second reason of why leaves, stems or roots are fragrant is to deter plant parasites, fungi and microorganisms. Fragrant essential oils in plant tissues destroy pathogens and, as they are usually bitter, spoil the taste which discourages animals from eating the plants. That is why plants with a strong aroma have healed, fungicidal and germicidal properties. Man, like other animals, can distinguish between scents and remember them. They may be innumerable and the memories which scents evoke help you travel backwards in time.
Humans, like other animals, possess the ability to distinguish between scents and memorize them. Their number can be enormous and the memories recalled by scents can constitute for us a travel many years back in time.