The Leaf Oils of the Australian Species ofCitrus(Rutaceae)

The leaf oils of the six species of Citrus that are endemic to Australia have been investigated. C. australasica produced an oil in which the principal components were bicyclogermacrene (19–28%), germacrene-D (2–8%), δ-elemene (0.5–11%) and limonene (12–24%). C. australis oil was dominated by α-pinene (68–79%). The oil from C. garrawayi appeared to be of two forms, (1) in which the principal components were the monoterpene α-pinene (18–40%), together with β-caryophyllene (7–12%), α-humulene (2–17%), globulol (4–10%) and viridiflorol (4–10%), and (2) which lacked α-pinene and had β-caryophyllene (17–30%), globulol (7–10%) and viridiflorol (7–10%) as principal components. C. glauca contained α- and β-pinene(24–47% and 12–17%, respectively) and the two furanoid forms of linalool oxide (0.8–15% total) as principal components. The oil of C. gracilis contained γ-terpinene(33.8%), p-cymene (14.8%), bicyclogermacrene (10.2%) and (E)-nerolidol (20.4%) as principal components, accounting for 80% of the oil. C. inodora gave an oil in which germacrene D (0.4–24%), germacrene B (1–9%) and bicyclogermacrene (0.9–19%) were the principal components.