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.

Unripe, semi-ripe, and ripe fruits of E. dysenterica were collected in rural area of Abadia de Goias city (S 16° 45′ 1″, W 49° 25′ 5″, 850 m), Goias State, Brazil, in October 2002.

Limonene (25.8% and 24.6%), (E)-beta-ocimene (20.3% and 21.7%) and beta-pinene (12.0% and 14.2%) were the major compounds in the unripe and semi-ripe stages, respectively, while gamma-muurolene (25.8%), beta-caryophyllene (18.4%) and alpha-humulene (15.4%) became the major compounds in ripe fruits. The concentration of monoterpenes was high in the unripe and semi-ripe stages and decreased afterwards, while sesquiterpenes were intensively synthesized only in the last part of the ripening process.

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: 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.

Leaves were collected from P. dioica trees (fruiting - 4, non-fruiting - 4, unknown - 4) located in Shawbury, St. Ann during the month of August. Trees which had been observed in excess of 30 years to be fruiting or nonfruiting trees and young pimento trees of unknown fruiting ability which had not yet blossomed were selected.

Oil yields obtained from the leaves of non-fruiting pimento trees (2.13%) were on average lower than that recorded for the fruiting trees (2.67%), although when the t-test was employed there was no statistical difference between the two (p< 0.05). Since the aim of this study was to investigate the aroma differences in the bearing and non-bearing pimento trees, analyses of the essential oils were confined to the more odoriferous volatile components, the monoterpenes and phenylpropanoids. Compounds exhibiting significant differences in composition at p < 0.005 were alpha-thujene, myrcene, alpha-phellandrene, gamma-terpinene and terpinolene while eugenol was significantly different at p < 0.01. With the exception of eugenol, the other significantly different components of the leaf oil exhibited a ratio of approximately 2:1 for the bearing to non-bearing pimento trees.