ABSTRACT

In the past, several classifications were made within the morphologically and chemically diverse Origanum (Lamiaceae family) genus. According to different taxonomists, this genus comprises a different number of sections, a wide range of species and subspecies or botanical varieties (Melegari et al., 1995; Kokkini, 1997). Respecting Ietswaart taxonomic revision (Tucker, 1986; Bernath, 1997) there exist as a whole 49 Origanum taxa within ten sections (Amaracus Bentham, Anatolicon Bentham, Brevifilamentum Ietswaart, Longitubus Ietswaart, Chilocalyx Ietswaart, Majorana Bentham, Campanulaticalyx Ietswaart, Elongatispica Ietswaart, Origanum Ietswaart, Prolaticorolla Ietswaart) the majority of which are distributed over the Mediterranean. Also, 17 hybrids between different species have been described, some of which are known only from artificial crosses (Kokkini, 1997). Very complex in their taxonomy, Origanum biotypes vary in respect of either the content of essential oil in the aerial parts of the plant or essential oil composition. Essential oil ‘rich’ taxa with an essential oil content of more than 2 per cent (most commercially known oregano plants), is mainly characterised either by the dominant occurrence of carvacrol and/or thymol (together with considerable amounts of -terpinene and p-cymene) or by linalool, terpinene-4-ol and sabinene hydrate as main components (Akgül and Bayrak, 1987; Tümen and Bas¸er, 1993; Kokkini, 1997).