Samples of Glechoma hederacea were collected at full flowering in seven localities in Vilnius district (Lithuania) at 2005: A - Salininkai, B -Zolyno, C - Mistunai, D -Antakalnis, E - Nemencine, F - Seskine, G -Zujunai.

More than half of the oils were rich in sesquiterpene hydrocarbons (56.5-67.9%). The most predominant compound was germacrene D (14.1-20.7%). The other main constituents were gamma-elemene (9.0-16.0%), beta-elemene (8.7-12.9%), phytols (2.8-15.6%), (Z)-beta-ocimene (2.2-8.5%), 1,8-cineole (92.2-5.4%), beta-ylangene (2.7-4.1%) and germacrene B (2.2-3.9%). Forty-three identified compounds made up 89.1-96.2%. Four oils (A, D-G) might be attributed to germacrene / elemene chemotype and three samples (A-C) containing marked amounts of phytols beside above compounds were of germacrene/elemene/phytols chemotype.

H. pectinutu is an odoriferous plant and occurs as a natural weed on the Fiji Islands and in West Africa as a winter hardy bush. In India, it grows as an erect perrennial shrub in Assam, Bengal and Madras regions. Tlie leaves are ovate and the leaf margins range from crenate to serrate. The flowers are pale purple to yellow in cymose clusters, arranged unilaterally. The nutlets are small, oblong and black.

The major compounds present in the Indian oil were sabinene (27.8%), beta-pinene (6.7%), limonene (4.03%), alpha-terpinolene (6.0%), caryopliyllcne (17.2%), alpha-bergamotene (4.1%) and a C20H32-diterpene (5.8%). Other major hydrocarbons present were gamma-terpinene (1.4%), alpha-humulene (1.1%), beta-selinene (1.0%) and gamma-elemene (2.7%). The oil is rather poor in oxygenated terpenoids, the only major oxygen compounds detected were terpinen-4-ol(3.1%), spathulenol(1.1%), an unidentified sesquiterpene alcohol (1.4%) and trans-alpha-bergamotot (2.5%). The total oxygenated compounds constituted about 11% of the oil.

Plant material: Samples of L. latifolia were collected in August 1998 during the full flowering period (L/La) and in October 1998 during the fruiting period (L/Lb) from three different spike lavender populations located into the Cazorla, Segura y Las Villas Natural Park (Jaen province, Spain). The plant material from each population consisted of the twigs of several single plants. L/La (Location: 'Garganta de Hornos', Altitude (m): 950, Harvesting date: August 14, 1998, Phenological stage: Flowering); L/Lb (Location: 'Garganta de Hornos', Altitude (m): 950, Harvesting date: October 15, 1998, Phenological stage: Fruiting).

The small amounts of linalool needed to match the standard can be reached in a natural way (from full flowering to fruiting) which means it is important to choose the most convenient time of harvest in the studied area.

Plants were collected in the Inner plain, the Sharon plain and the kava valley.

The major constituent of all three oils was found to be 1,8-cineole (26.4-34.5%) followed by menthone (10.0-16.7%), pulegone (7.0-7.5%), and isomenthone (4.7-7.8%). Despite some differences in the component proportions, the plants of all three populations clearly belong to the same chemotype.

Biological material for these investigations comes from two distant collection sites: Suva planina (mountain in the east of Serbia) and Durmitor (mountain in Montenegro). All specimens (aerial parts of the plants) were collected in 1994 in the blooming stage and/or in the pre-blooming stage.

The results obtained show that though the yields of oils were barely influenced by plant growth stage, they varied appreciably according to the origin of the plant material: pre-blooming, Suva Planina (Serbia): 0.67%; blooming, Suva Planina (Serbia): 0.70%; blooming, Durmitor (Montenegro): 0.40%. Thirty-six components were identified. 1,8-Cineole was always predominant (60%); its concentration was lower (40%) just before blooming. Also present were germacrene D (2-15%), beta-caryophyllene (4-7%), alpha-terpineol (5-7%) and caryophyllene oxides (2-6%). In general, the chemical composition of N. nuda depended more strongly on growth stage than habitat. The only exception was caryophyllene oxide which was three times more abundant in the oil from Montenegro than in that from Serbia.

Samples of R. officinalis were collected in April 1998 during the full flowering period (Ro-1a), between June and July 1998 during the fruiting period (Ro-1b) and in December 1998 during the hibernation period (Ro-1c) from Cazorla, Segura y Las Villas Natural Park (province of Jaen, Spain). The plant material consisted of ca. 10 twigs per plant (with blossoming tips or not, depending of the harvesting date) from 5-10 single plants. Ro-1a (Location: Las Chozuelas, Altitude (m): 1150, Harvesting date: April 21, 1998, Phenological stage: Flowering); Ro-1b (Location: Las Chozuelas, Altitude (m): 1150, Harvesting date: June 19, 1998, Phenological stage: Fruiting); Ro-1c (Location: Las Chozuelas, Altitude (m): 1150, Harvesting date: December 30, 1998, Phenological stage: Hibernation).

The highest oil yields (161.8%) were recorded during the fruiting period (summer). In general, minimum amounts of camphor and maximum amounts of alpha-pinene were observed in winter. The concentration of 1,8-cineole was almost constant throughout the year, though other oil constituent levels varied randomly with the plant life cycle

Clones of T. daenensis populations were collected from 11 locations including seven locations in Fars and four locations in Kohkiluyeh provinces of Iran. The clones of T. daenensis populations were transplanted to the farm at IANRRC Research Station, located in NajafAbad (18 km west Isfahan, 32° 36′ N, 51° 26′ E and 1612 m asl) in March 2002 . Clones were grown in 5 × 2 m plots with 50 × 50 cm planting density. Fertilizers were applied prior to planting at a rate of 60 kg P/ha and 50 kg N/ha. After 3 years (2004), the aerial parts of plants were harvested at full flowering stage, dried at room temperature, and stored until analysis inside paper bags in a cool and dark place. Td1 (Fars Province, Eghlid, Asepas; Altitude: 2000); Td2 (Fars Province, Sourian, Bavanat; Altitude: 2500); Td3 (Fars Province, Abadeh, Keverlar; Altitude: 2280); Td4 (Fars Province, Abadeh -Shiraz Rd, Kolikosh; Altitude: 2400); Td5 (Fars Province, Shiraz -Yasouj Rd, Komehr; Altitude: 2415); Td6 (Fars Province, Yasouj -Shiraz Rd, Margoon; Altitude: 2170); Td7 (Fars Province, Shiraz -Isfahan Rd, Pasargad; Altitude: 2190); Td8 (Kohkiluyeh Province, Sisakht, Gol; Altitude: 2570); Td9 (Kohkiluyeh Province, Kakan; Altitude: 2200); Td10 (Kohkiluyeh Province, Yasouj -Sepidan Rd, Mahparviz; Altitude: 2660); Td11 (Kohkiluyeh Province, Sepidar, Pazanan; Altitude: 2600).

Carvacrol, thymol and geraniol were found as the main constituents in the oils of the tested populations. Variation of the oils in populations was subjected to cluster analysis and three different chemotypes including carvacrol (47.3-80.1%), thymol (53.1-72.2%) and geraniol (65.6-75.7%) were identiified. Other important components were beta-caryophyllene (1.7-9%), p-cymene (0.1-10.9%) and gamma-terpinene (0.1-7.8%). Although Thymus is known as having high thymol content in its oil, it is revealed that T. daenensis subsp. daenensis has also a high potential for carvacrol and geraniol constituents in the oil. The largest similarity of the oil components of populations was detected between Td4 and Td7 and the lowest was revealed between Td8 and Td9. The differences in the oil content and composition of the populations could be attributed to their genetic variability and they could be a good genetic source for breeding purposes.

Aerial parts of T. fontanesii were collected during June 2004, in full blossom, in the Province of Tlemcen in four locations: Sidi-snoussi, Remchi, Sebdou et Sebaa-chiouki and again, during June 2005, in the last location.

The yield of oil obtained from the aerial parts of Thymus fontanesii harvested in the Province of Tlemcen (Algeria), calculated on dry material basis,varied slightly from station to station: Sebaa-chiouki = 5.20%, Sebdou = 5.25%, Sidisnoussi = 5.32%, Remchi = 5.46%. The composition of the four samples was quite similar, carvacrol (66.7-69.5%) being by far the main component. Other constituents, present at appreciable contents, were p-cymene (6.1-9.1%), gamma-terpinene (6.0-9.6%), linalool (3.0-4.0%), alpha-pinene (2.5-3.0%), myrcene (1.2-1.5%), and alpha-terpinene (1.1-1.4%). Conversely, thymol accounted only for 0.6-0.7% of the composition. Moreover, a sample harvested at Sebaa-chiouki, in June 2005, produced on oil with the same composition (68.3% of carvacrol). Obviously, aerial parts of T. fontanesii from the province of Tlemcen produced an oil whose composition differed substantially from that of the oil obtained from the same species harvested in Setif province and Constantine area (Algeria), dominated by thymol (67.8% and 68.2%, respectively).