grass-oil

from The Century Dictionary.

• noun A name given to the fragrant oils procured in India by distillation from several species of Andropogon, especially A. Nardus, yielding citronella-oil, A. citratus, yielding lemon-grass oil or oil of verbena, and A. schœnanthus, from which is obtained oil of ginger-grass or oil of geranium. They are used chiefly in perfumery.
• noun Much has been learned of late years in regard to the chemical composition of the fragrant grass-oils which hold a prominent place in modern perfumery. The most important constituents are an alcohol, geraniol (C₁₀H₁₈O), in Indian grass-oil or palmarosa oil, from Andropogon Schœnanthus; an aldehyde, geranial or citral (C₁₀H₁₆O), in lemon-grass oil, from Andropogon citratus; and another aldehyde, citronellal (C₁₀H₁₈O), in citronella-oil, from Andropogon Nardus.