Lots of flowers have their own, distinct smell. Humans' olfactory system might not be comparable to dogs or cats, but it's still enough to rely on with great many flowers, if one bothers to learn them by the odour.
In case someone who doesn't know Japanese was confused: The "Etou" (or more commonly romanized "etto") Takai used at one point is like "anno" a Japanese filler word like "umm" or "well" in English.