The members of this genus are herbs or dwarf shrubs with often lanate or tomentose alternating leaves, numerous white or coloured bracts and white or yellow flowers. Along with the taxonomically recognised Helichrysum species a significant number of evolved hybrids is also found (Jahn and Schoenfelder, 1995). The individual morpho-anatomical characteristics of these hybrids in several cases can be deceiving and can lead to wrong assignments to recognised taxa (Tsoukatou et al., 1998).

In the framework of our chemical and biological investigations on the volatile metabolites of Greek endemic and Mediterranean plant species (Roussis et al., 2000; Roussis et al., 1998;) we recently were able to collect and study specimens of eight Helichrysum species (Helichrysum orientale; Helichrysum heldreichii; Helichrysum italicum ssp microphyllum; Helichrysum italicum ssp italicum; Helichrysum amorginum; Helichrysum taenari; Helichrysum stoechas ssp barrelieri; Helichrysum doerfleri) and a hybrid growing in different geographical compartments in Greece.

The high degree of genotypic variability, observed in a number of Helichrysum species, is reflected in the biochemical variability, which is usually studied at the levels of terpene composition and isozyme variation. Terpenes besides some environmental variabilities are dependent upon the plant's genotype and have been extensively used for taxonomic purposes.

More than one hundred volatile metabolites were identified by means of GC and GC-MS and were submitted to statistical analyses. Distinct chemical profiles characteristic to the studied taxa were assigned on the basis of the four most significant chemical contributors. E-caryophyllene, caryophyllene oxide, carvacrol, geraniol and b-selinene were the constituents with the highest discriminate value. The hierarchical order of the analysed species in the terpene space matched quite well with the corresponding dendrogram of the morphoanatomical space.