Distribution of Flavonoids as Chemotaxonomic Markers in the Genus Origanum L. and Related Genera in Labiatae

Abstract

Origanum L. is a taxonomically complex genus containing approximately 26–30 species. Its geographical distribution extends from North Africa and Western Europe to Central Asia. One species Origanum vulgare has a very wide distribution from the Azores to Taiwan, whereas most species are endemic to a single island or mountain. The centre of diversity is in the Mediterranean basin where over 70% of the species are found. They usually occur in mountainous regions ranging from 500 to 1500 metres in altitude in rocky places with calcareous soils. The species of Origanum like so many other Mediterranean labiates, are distinctly shrubby or at least woody at the base, and rich in volatile oils. These oils are found in glands which are distributed mainly in the leaves. The genus has been variously treated in the past, some authors recognizing a number of distinct genera e.g. (2), others recognizing only sections e.g. (1): both treatments are still in current use (3, 11).