PATTERN OF GEOGRAPHIC-VARIATION OF ORIGANUM-VULGARE TRICHOMES AND ESSENTIAL OIL CONTENT IN GREECE

The variation of the total plant pubescence and essential oil content of Origanum vulgare plants grown all over the species range in Greece has been studied. In respect to their glandular and non-glandular trichomes, O. vulgare plants are differentiated along a direction from eastern and central Aegean islands, through Crete and Peloponnese, to the northern part of Greece. The same variation pattern is found when the essential oil content of O. vulgare plants is considered. Along this direction, a gradual change of the climate from the Real Mediterranean to the Continental Mediterranean type occurs. Plants grown in the Mediterrean climatic zones are characterized by numerous sessile glands and are essential oil-rich (ssp. hirtum), whereas those of the Continental type climate have few glands and are oil-poor (ssp. viridulum and ssp. vulgare).