Whole leaves and inflorescences of two wild strawberry cultivars ('Rugia' and 'Baron von Solemacher') harvested in 2008 during the agrotechnical experiment performed by Department of Vegetable and Medicinal Plants, University of Life Sciences in Lublin, were used as a material for determinations. Samples were collected before noon at sunny and dry days at the beginning of wild strawberry's flowering stage. Material was dried up to 35 ℃ in shadow and air just after the harvest.

Depending on a cultivar, air-dry inflorescences from wild strawberry contain from 0.21% ('Baron von Solemacher' cv.) to 0.30% ('Rugia' cv.), whereas leaves contains from 0.46% ('Baron von Solemacher' cv.) to 0.62% ('Rugia' cv.) of essential oils. GC/MS analysis of essential oils achieved from studied materials revealed presence of 70 (including 59 identified) compounds in leaves of 'Rugia' cv. and 58 (including 50 identified) compounds in leaves of 'Baron von Solemacher' cv. Essential oils from inflorescences of 'Rugia' cv. contained 52 (including 47 identified), while 'Baron von Solemacher' cv. contained 54 (including 46 identified) compounds. The chromatographic analyses by GC-MS revealed that myrthenol, nonal, linalool and phthalide dibuthyl dominated in essential oils obtained from leaves, while myrthenol, citronelol, linalool and geraniol - from those of inflorescences. There were qualitative differences between oil components at both studied materials and differentiation between both cultivars, as well.

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.

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

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.