Arternisia and Tanncetzrm (fam. Compositae) are widely-distributed genera each comprising several hundred species. Several leaf oils of Artemisia species have been used medicinally and industrially, and rlunierous phytochemical investigations have been made (Fa h m y et al. 1 9 6 0 ) but few (e g., K h is a m u t d i n o v and and G o r y a e v 1959; G o r y a e v et al. 1962, 1964; M a n j a r r e z and M e d i n a 1964; I s h i b a s h i et al. 1965; T s u b a k i et al. 1966; G o r y a e v et al. 1 9 6 8 ) are acceptable by modern standards. T. vulgare L. is the only member of the other genus that has been similarly quantitatively investigated (v o n R u d l o f f and U n d e r h i l l 1965; B a n t h o r p e and W i r z -J u s t i c e 1 9 6 9 ) . In order to find sources of camphor and thujone suitable for biosynthetic studies we have screened the leaf oils of various Artenzisia and Tanaceturn species grown under the same conditions in England. A secondary objective was to determine any monoterpene pattern characteristic of these two genera. Experimental a) Plnnt Material. Many mature specimens were obtained from the Royal Botanic Gardens, Kew, and the Chelsea Physic Garden, London. Young plants of other species were purchased from Messrs. Hillier, Winchester; and A. cnlifornica was obtained from Professor C. M ii l l e r , Santa Barbara, California, and naturalised for 18 months. Seeds of the other species were obtained from Botanical Gardens a t Barcelona, Rome, Naples, Pisa, Palermo and Istanbul and were cultivated outdoors in Central London.h) Analysis of Oils. Freshly gathered foliage (late September; terminal 20 cm of mature shoots; SO to 200 gm) was pulverised in liquid nitrogen and extracted with petroleum spirit, b. p. 40' (ca. 20 ml). T h e solid residue was steam distilled with the receiver a t -78'; the distillate was salted-out with ammonium sulphate and extracted with the organic fraction previously collected. This procedure is much more efficient than the traditional steam-distillation process (cf. S c h r a t z and W a h li g 1965). Typically, yields of oil were 0.2 to 1.5% of the wet weight of the foliage.The extract was analysed by gas-liquid chromatography (glc) and then concentrated (to about 4 ml.) to enable the major components to be separated by preparative-scale glc for spectral identification. Helical copper columns (600 cm X 0.6 mm o. d.) were used in either a Pye Mark 104 or a Griffin and George Mark 111 Flame-Ionisation Chromatograph with four stationary phases; (i) Carbowax 20M (10% WIW), (ii) (3-0-oxydipropionitrile (10% WIW), (iii) APEC (10% WIW) and (iv) dionyl phthalate (15% W/W) all coated on G-Cel (60-80 mesh; acid-alkali washed).Operating temperatures were 75' and 150' in turn; the gas flow (nitrogen) was 50 ml min. -'; and the injector ports and detectors were held 10' lower than the column. N o dehydration or isomerisatiocl of standards occt~rred under these conditions. Banthorpe et al., Heft 2 Compounds present in greater than 5% W/W of the oil were isolated and char...

T h e pioneering investigations of von R u d 1 o f f , M i r o v , Z a v a r i n and others have shown that the pattern of monoterpenes in the leaf oils of related species of higher plants can be used as a tool in chemosystematic studies. This work has recently been briefly reviewed (B a n t h o r pe et al., 1972). Although numerous other phytochemical investigations have been made on leaf oils, with few exceptions these have been semi-quantitative or have used either commercial oils or a few species grown under particular (sometimes widely different) climatic conditions. Systematic investigations using modern methods of analysis of the monoterpenes of selections of species from particular genera grown under conditions where differences due to habitat and environment are minimised are virtually non-existent. Recently we reported systematic studies on Artemisia and Tanacetum species (B a n t h o r p e et al., 1971). We here have extended the approach to Juniperus and Thuja species (fam. Cupressaceae). The constituents of the berry and wood oils of Juniperus species have often been investigated (G u e n t h e r , 1952) but except for the work mentioned in the Discussion little is known of the leaf oils of these species. Experimental a) Plant material. Our specimens were purchased as two or three year old stock from either Hillier and Sons (Winchester, Hampshire) or the Glasfryn Forest Nursery (Pencaenewydd, Caernarvonshire) and were naturalised in the Central London or (for 7'. orientalis) in a suburban garden for a further two years before material was harvested from the saplings (typically 200 to 300 cm high). Material from mature specimens of most species (for comparison purposes) was obtained from the above sources; the Royal Botanic Gardens at Kew and Edinburgh; the National Pinetum, Bedgebury, Kent; the Chelsea Physic Garden, London; and the Botanical Gardens of the Universities of Oxford and Cambridge. 1. communis L. was collected from the North Downs near Dorking, Surrey. Foliage from two or three trees of each species was gathered in late October-November from reminal branches (20cm) a t different heights above the ground and the batch from each plant was individually worked up for analysis. b) h a l y s i s of Leaf Oil. Preliminary experiments showed chat there was no significant difference in the composition of the oil of 1. communis L. obtained from green o r brown parts of the terminal branchlets, and so the collected material was worked-up without sorting. Freshly-gathered foliage (c. 200 g) was pulverised in liquid nitrogen and the solid residue plus sodium bicarbonate (5 g) was steam distilled with the receiver a t-7S0. The neutral oil

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