This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Citronella Oil - This is obtained from Andropogon Nardus L., a grass indigenous to Ceylon, growing wild and also largely cultivated there. It is obtained by distillation, smells agreeably. Singapore furnishes considerable quantities.
Lemon-grass oil, sometimes also called verbena oil (which see). This is distilled from Andropogon citratus, comes also from the East Indies, especially Ceylon and Singapore. The oil is obtained by distilling the grass with water; it is nearly colorless; its smell resembles to some extent that of lemon.
Ginger-grass oil or Indian Geranium oil, also called Turkish oil of Geranium, obtained from Andropogon Schoenantus L., an Indian grass, comes from Bombay, smells agreeably, rose-like; it is imported into Turkey for the purpose of adulterating oil of rose.
Vetivert oil (Cuscus), obtained from the roots of Andropogon muri-catus, a grass indigenous to India. The roots are exported from Calcutta and distilled in England and Germany, when volatile oil of a green color, aromatic, separates.