Palmarosa (Cymbopogon martinii) is a large herbaceous plant belonging, like citronella, to the Poaceae family. It is native to India and Nepal. When crumpled, its long and narrow leaves release a fragrance similar to that of roses. Its flowers, arranged in plumes, are similar to those of geranium.
 
Due to its sweet, floral rose scent, Palmarosa is often erroneously labeled and sold as Rose Geranium even though it bears no relation to that wonderful plant. It is also used to adulterate true Rose Geranium (but not ours!).