As autumn unfolds, its splendors permeate everyday life: foliage falls on city streets and in forests, and the scent of pumpkin and spices burns in lobbies and living rooms all over. But one naturally occurring aroma eludes some noses and pleases those that can smell it: the katsura, or “caramel tree.” Native to Japan and China (and, at one point, possibly North America), the Cercidiphyllum japonicum smells of burned sugar when its hue changes from a rich purple to a wet yellow. The chemical responsible for the scent, maltol, can also be found in breads, warmed butter, cocoa, and coffee, researchers say. Unfortunately, though, as our senses of smell are as individually coded as our face and body type, not everyone notices this fragrance. Read more at The New York Times.