Cistus ladanifer was collected from two sites, in July-August 2001, after the flowering season. The major quantity was brought from the wild, where the plant was growing in the mountainous region of the center-interior of the country (site 1). A smaller amount was harvested from a cultivated plant in the north of Portugal (site 2) that was propagated from a wild plant found in the dry plain region in the South of Portugal.

Considering the oil composition of cistus plants from different sites, there were found some differences. The cistus oil of site 2 had a high content on the ocimenone isomers, an absence of trans-pinocarveol and unknown (compound 17) and a higher quantity of less volatile compounds such as sclareol oxide and 15-nor-labdan-8-ol. Cistus oil from site 1 was richer in sesquiterpene alcohols and 2,2,6-trimethylcyclohexanone. The amount of ambrox was the same for both oils. Considering the use of fresh or dry plant, the composition of cistus from site 2 was more affected, decreasing the amount of components of middle to high volatility and increasing the amount of the less volatiles. Drying promoted the doubling of the amount of ocimenone isomers in cistus oil from site 2 and of unknown (compound 21) and sesquiperpene alcohol (compound 29) in cistus from site 1. Again the quantity of ambrox was the same for both oils.

Fresh leaves of the E. camaldulensis varieties(var. mysore and var. Catharine) were collected from 12 mature trees growing in Agodi Gardens, Ibadan, Nigeria.

The quantitatively significant constituents in die leaf oil of the two E. camaldulensis varieties were beta-pinene (9.0-17.5%), 1,8-cineole (32.8-70.4%), (Z)-beta-ocimene (11.6%) and alpha-pinene (8.8%). Monoterpenoids also made up the bulk of the two volatile oils (89.0-95.7%).

Eucalyptus urophylla and E. grandis were collected in January (summer) and August (winter) 2006 at the mature vegetative state from Goiania city Brazil, and identified by one of the authors (E.P.F.). Leaves from 5-11 randomized individual plants of the same age representing the local population were collected as homogenous samples in each season, dried at room temperature.

The results were submitted to Principal Components and Clusters Analysis which enabled four groups of oils to be distinguished with regard to specimens and harvest seasons: clusters I and II with only E. grandis samples collected in the cold and dry winter and the hot and humid summer, which were characterized by a high percentage of isoleptospermone (9.6% and 13.2%), alpha-pinene (12.2% and 24.7%), p-cymene (20.5% and 14.5%), and alpha-terpineol (14.3% and 4.9%), respectively; clusters III and IV only associated with E. urophylla samples collected in summer and winter with 1,8-cineole (36.6% and 44.7%) and alpha-terpinyl acetate (7.0% and 11.7%) rich oils.

Plant material was collected at vegetative stage (stems and leaves,September 2005) and at flowering stage (leaves and flowers,December 2004), inCuritiba,Parana state, Brazil.

Thirty-four components were identified, representing more than 80% of total oil. The major components were beta-caryophyllene (flowers-12.8%), caryophyllene oxide (stems-17.2%), globulol (stems-16.5%; leaves-22.5% at vegetative stage and 18.9% at flowering stage), 1-epi-cubenol (stems-10.9%), epi-alpha-muurolol (stems-16.8%) and alpha-cadinol (stems-12.1%; flowers-10.1%).

The plant material was collected in eastern Lithuania (July-August, 2002). Numbers of growing localities of H. arenarium with yellow (Y) and orange (O) flowers were as follows: Svencionys district (Zalavas) and Ukmerge district (Sventupe).

The 68 constituents identified comprised 73.8-90.7% of the total oil content. It was found that the principal constituents were: beta-caryophyllene (in three inflorescence and one leaf oil), delta-cadinene (in two leaf oils), octadecane (in one leaf oil) and heneicosane (in one inflorescence sample). Monoterpenes and oxygenated monoterpenes made up 4.0-13.9%, aliphatic hydrocarbons 0.4-35.3%, and sesquiterpenes 24.7-71.2% of the oils.

Samples of M. ericifolia leaves were obtained from 19 locations as follows: DL3104- 3110, Coopernook, New South Wales (NSW), 31° 49′ 31″ S, 152° 36′ 48″ E (Site No. 1); DL3114-3120, Hawks Nest, NSW, 32° 40′ 09″ S, 152° 10′ 12″ E (Site No. 2); DL3240-3244, Hexham, NSW, 32° 48′ 50″ S, 151° 42′ E (Site No. 3); DL3245-3249, The Entrance, NSW, 32° 22′ 24″ S, 151° 28′ 19″ E (Site No. 4); DL3397-3401, Tuggerah Lake, NSW, 33° 21′ S, 151° 27′ E (Site No. 5); DL3250-3254, Georges River, NSW, 33° 58′ 42″ S, 151° 00′ 14″ E (Site No. 6); DL3255-3259, Berry, NSW, 34° 46′ 37″ S, 150° 45′ 27″ E (Site No. 7); DL3260-3264, Lake Durras, NSW, 35° 36′ 00″ S, 150° 16′ 17″ E (Site No. 8); DL3265- 3269, Wallaga Lake, NSW, 36° 23′ 43″ S, 150° 03′ 04″ E (Site No. 9); DL3270-3274, Wallagoot, NSW, 36° 44′ 50″ S, 149° 55′ 46″ E (Site No. 10); DL3275-3279, Genoa, Victoria (Vic), 37° 25′ 56″ S, 149° 38′ 41″ E (Site No. 11); BVG3024- 3028, West of Lakes Entrance, Vic, 37° 48′ S, 148° 03′E (Site No. 12); BVG3014-3018, West of Lang Lang, Vic, 38° 13′ S, 145° 30′ 13″ E (Site No. 13); BVG3019-3023, East of Welshpool, Vic, 38° 38′ 28″ S, 146° 30′53″ E (Site No. 14); ACC1019/1-2, 5-7, Nelson on the Glenelg River, Vic, 38° 03′ S, 141° 00′ E (Site No. 15); KJ1-5, Airport Flinders Island, Tasmania (Tas), 40° 05′ S, 148° 00′ E (Site No. 16); KJ6-10, Lackrana Road Flinders Island, Tas, 40° 18′ S, 148° 06′ E (Site No. 17); ACR1848/1-3, Woolnorth Point, Tas, 40° 38′ 30″ S, 144° 43′ 30″ E (Site No. 18); JB4509, Robins Island Track, Tas, 40° 45′ S, 144°53′E (Site No. 19). The majority of samples were collected during June to December 1999 with the exceptions being sites 5, 15 and 18, which were collected during July to October 2000. Leaf material totaling about 100 g of fresh leaves and twigs was obtained mainly from five widely spaced individual trees per location.

Oil composition varied quantitatively throughout the species range rather than qualitatively in an apparent association with latitude of occurrence. Linalool and linalool oxide were abundant in the oils from the north of the species range in New South Wales with a gradual southerly decline in these compounds to central Victoria with concomitant increase in the proportions of 1,8-cineole, alpha-terpineol and limonene. The most southerly populations sampled in southern Victoria and Tasmania gave oils containing relatively high proportions of 1,8-cineole (mean 34.5%) and low proportions of linalool (3%). Four populations from the Central Coast of NSW (Coopernook, Hawks Nest, The Entrance and Tuggerah Lake) provided the greatest opportunity of identifying seed trees that combine the attributes required for plantation development. The tree that had the best combination of oil traits (DL 3116 from Hawks Nest) had an oil yield of 4.5%, a linalool content of 60% and a 1,8-cineole content of 16%.

Plant material: Leaves of M. quinquenervia were collected from January to October during the ten year period (1992-2001) on mainly East part of Madagascar island and in particular on Toamasina, Mananjary, Manakara, Farafangana, Vangaindrano, Moramanga, and Ambatondrazaka locations. Olfactory chemotype selection: During the years 1992-1995, since the price for (E)-nerolidol and viridiflorol chemotypes was very strong, leaf collection was done on trees chosen after olfactory selection by a chief harvester who compared the olfactory threshold of crumple leaves with our clearly identified oil samples. After 1996, collection was done at random and no particular attention in leaf harvesting was taken.

Niaouli essential oils from Madagascar were classified into three chemotypes using Principal Component Analysis (PCA): a cineole chemotype (49-62%), a viridiflorol chemotype (21-36%) and an (E)-nerolidol chemotype (56-95%). The 1,8-cineole chemotype is widespread, representing 92% of the samples investigated if the leaf collection is done at random.

Experimental: Two hundred grams of healthy mature intact leaves were harvested from each of the taxa growing on their own rootstocks at the UC South Coast Research and Extension Center. flocc = P. americana var. floccosa from Mexico D-7; stey = P. americana var. steyermarkii from Mexico El Salvador 3-22-16; nubi = P. americana var. nubigena from Guatemala 45-C-1; mex = P. americena var. drymfolia from Tasco, Mexico; guat = P. americana var. guatemalensis cult. Nimlioh from Florida; bwl = P. ameticana var. americana cult. Trapp from Florida.

Analysis of oils showed the presence of over 90 components, of which 76 were identified. P. schiedeana oil was found to contain alpha-pinene (23.7%), beta-pinene (23.2%) and beta-caryophyllene as major components. The major constituents of P. americana var. floccosa and P. americana var. steyermarkii were alpha-pinene (10.9%, 7.6%), beta-pinene (20.6%, 10.4%), alpha-terpineol (9.6%, 7.9%), beta-caryophyllene (12.6%, 8.4%), viridiflorene (0.1%, 10.3%) and globulol (0.1%, 9.2%), respectively. The oils of P. americana var. nubigena and P. americana var. drymifolia contained alpha-terpineol (18.4%, 393%) and methylchavicol (12.4%, 40.2%), as major components, respectively. P. americana var. guatemalensis was found to be rich in beta-caryophyllene (38.3%), while the oils of P. americana var. americana and P. primatogena contained alpha-pinene (27.5%) and beta-pinene (40.9%), and alpha-pinene (24.6%), beta-caryophyllene (20.7%) and germacene D (10.1%).

Sage plant material was collected from two different localities (altitudes 110 and 400 m) in central Herzegovina near Mostar and at four different stages of development: vegetative period (leaves and stalks, January 2003), prior to flowering (leaves and stalks, April 2003), in the course of flowering (flowering tops, leaves and stalks, May 2003) and after flowering (leaves and stalks, August 2003).

The highest oil yield of the plant was after flowering (August). The oil samples obtained prior to flowering (April) and in the course of flowering (May) yielded remarkably less than those after flowering (August) and in the vegetative period (January). An unexpected high oil yield of the plant in the vegetative period (January) is probably due to lower moisture content in this stage of development. The oil yields ranged from 0.29% to 0.64% (altitude 110 m) and 0.45% to 1.07% (altitude 400 m), which reveals that altitude also has significant influence on oil yields. The oils from plant materials gathered prior to flowering (April) and in the course of flowering (May) were found to contain significantly higher percentages of alpha-humulene, manool, viridiflorol and caryophyllene, while the oils produced after flowering (August) and in vegetative period (January) have had higher percentages of alpha-thujone and camphor. Although the altitude has had an obvious influence on oil yields, it did not have significant influence on the qualitative and quantitative composition of their constituents.

Aerial parts of T. larvatum were collected in July and August during a five-year period, starting in 2001, in Montenegro on several locations: Planinica (Sample a), Visitor (Sample b) and Sinjajevina (Sample c).

Sixty-four components were identified, representing 83.1%, 96.6% and 89.4% of the total oils content in the Planinica [Sample a], Visitor [Sample b] and Sinjajevina [Sample c], respectively. The major constituent in Samples a and b , was oxygenated monoterpene, trans-sabinyl acetate (38.1% and 55.8% respectively). Monoterpene hydrocarbons, beta-pinene (13.5%) and santolinatriene (30.6%), were found to be the dominant components in Sample c. The toxic trans-sabinyl acetate was present only in traces in this sample. trans-Chrysanthenyl acetate, as one of major components in feverfew essential oil, has not been previously identified in the investigated essential oils.

The aerial parts of T. flavum were collected in different periods from December to July 2006, from plants growing along the Ionic coast of Sicily (Italy). LF 1-LF 2-LF 3: represent the composition of leaf oils of plant samples collected in December (vegetative stage), February (pre-flowering stage) and April (budding stage) respectively; FL: flower oil; FR: fruit oil.

Some components, in all investigated plant parts, remained more or less constant during all the different phases of the plant cycle life. Worthy of note, considering the leaf oils, was that beta-pinene, limonene and germacrene D increased in the pre-flowering stage, while a series of esters and alpha-copaene, beta-caryophyllene, viridiflorol, Tmuurolol and phytol increased in the budding stage (LF3); the vegetative stage oil is generally characterized by a rich chemical composition and some constituents such as isoamyl hexanoate, alpha-humulene, bicyclogermacrene, beta-bisabolene and alpha-bisabolol reached their highest levels in this oil. In the flower oil, linalool and 1-octen-3-yl acetate were the main components compared to the amounts found in the other oils. Fruit oil composition was relatively oil poor, with beta-bisabolene, caryophyllene oxide, cadin-4-en-1-ol and phytone as the major constituents.