Citronella is the common name for a grassa,Cymbopogon nardus, which is native to India and southeast Asia. Citronella oil is a yellowish essential oil distilled from the leaves of either of two grasses, Cymbopogon nardus or C. winterianus. This aromatic oil is inexpensive, and widely used in cheap perfumes and as a fragrance in soaps. It is also best known as an insect repellent. Citronellol, derived form citronella oil, is a chief constituent of geranium oil, another is geraniol. Both are used in the production of perfumes. (sweet, rose, lilac, geranium ) .