Plant material of A. verlotiorum was harvested near Marseille (France) in May (before blooming) and November (full flowering) 2000.

For the oil from the vegetative plants, 50 compounds, representing 99.8% of the oil were characterized. Fifty-nine compounds, representing 99.6% of the oil were identified in the oil from flowering plants. In both cases, the constituents were mainly oxygenated monoterpenes (74% and 88%). The composition of each oil showed only a few differences, as the main components were alpha-thujone (55% and 44%), 1,8-cineole (5% and 15%), beta-caryophyllene (13% and 7%) and beta-thujone (5% and 11%), in the oils of the vegetative plant and flowering plant, respectively. The proportions of the oxygenated compounds seemed to increase during flowering.

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.

Fresh aerial parts of the S. trilobata were collected from CSIR-Central Institute of Medicinal and Aromatic Plants, Research Centre Pantnagar (Uttarakhand) in summer (vegetative stage), rainy (vegetative stage), autumn (flowering stage) and winter (flowering stage) seasons. The experimental site is located between coordinates 29.02° N, 79.31° E and an altitude of 243 m in foothills of northern India.

Volatile oil yield varied from 0.18 to 0.25% in different seasons, with the maximum in winter season. Altogether, 43 constituents, representing 96.1-97.3% of the total oil composition were identified. Major constituents of the oils were alpha-pinene (78.6-83.3%), alpha-phellandrene (1.3-4.1%), sabinene (1.4-1.9%), limonene (1.2-1.9%), beta-pinene (1.0-1.6%), camphene (0.7-2.0%), 10-nor-calamenen-10-one (<0.05-1.5%), germacrene D (0.1-1.4%) and gamma-amorphene (<0.05-1.3%). The comparative results showed no big differences in the oil composition of this plant due to season of collection.

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.

Aerial parts of the plant were collected from four localities: A = Kirklareli: Karadere in May 1991; B = Kirklareli: Karahamza Village in May 1990; C = Kirklareli: Evciler Village on 13 June 1993; D = Kirklareli: Korukoy on 25 May 1994

The four oils obtained from plants collected in different localities of the same region gave quite different compositions as follows: A: thymol (10.5%), 1,8-cineole (9.96%), p-cymene (9.48%), carvacrol (5.28%); B: beta-caryophyllene (29.50%), carvacrol(20.59%); C: thymol (34.7%), beta-caryophyllene (12.74%), carvacrol (5.24%); D: beta-caryophyllene (56.48%), germacrene D (11.12%), carvacrol (4.85%). Since the identities of the plant materials were checked repeatedly, any misidentification is ruled out. Except for A and C, all the other materials showed beta-caryophyllene as the major constituent. Carvacrol (20.59%) was present in good amount in the oil of B. In A, however, high percentages of 1,8-cineole (10%) and p-cymene (9.5%) were significant. This oil contained only a trace amount of beta-caryophyllene. Four isomeric caryophyllene alcohols were detected in the oil B. The results clearly indicate that the oil of T. striatus var. interruptus has no consistency and we can safely suggest that there are at least three chemotypes, namely thymol/1,8-cineole/p-cymene-type; thymol/beta-caryophyllene-type; and beta-caryophyllene-type, of this species.