Putievsky, E., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar, Post, Haifa, 31-999, Israel
Ravid, U., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar, Post, Haifa, 31-999, Israel
Dudai, N., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar, Post, Haifa, 31-999, Israel
Katzir, I., Institute of Field Crops, Agricultural Research Organization, Newe Ya'ar, Post, Haifa, 31-999, Israel
Carmeli, D., Department of Botany, Tel-Aviv University, Tel-Aviv, Israel
Eshel, A., Department of Botany, Tel-Aviv University, Tel-Aviv, Israel

The essential oil content and compositon of Artemisia judaica L. from the Sinai Peninsula (Egypt) and the Negev Desert (southern Israel) are related to a variety of factors such as season, plant age, and different plant parts. Differences were found also from samples collected at various locations. The contents fluctuated with the season, reaching the highest level during the late summer. Seasonal variations in the essential oil content occur one month earlier in Sinai plants than in Negev plants. The essential oil content in the leaves is higher than in the branches and flowers. No differences were found in the relative percentage of the components in the essential oil from different plant parts. Essential oil of A. judaica plants from the two regions was of two distinct chemotypes. An artemisyl‐oil type was predominant in the Negev samples, while a piperitone‐oil type was predominant in those collected in southern Sinai. These differences were evident in samples collected in the wild in all seasons, over a period of two years. Seedlings grown in a controlled environment, from seeds collected in the two regions, exhibited the same differences. It is, therefore concluded that these differences reflect genetic differences between the two populations. Copyright © 1992 John Wiley & Sons, Ltd