[A glimpse of the history of the genus Artemisia from pollen analyses]

The first certain data about the pollen grains of Artemisia have been found about the Middle Miocene. A review of the recent works concerning Western Europe and Northern Africa allows us to have some confirmation of this point of view. The pollen of Artemisia is appearing in the Miocene (Serravallian) with very poor amounts, the first important spreading of this plant, as revealed by sporopollinic analysis, comes near the Tertiary-Quaternary boundary at the time of an important deterioration of the climate. For the Quaternary, Artemisia is often present with low percentages and is only developing during the glaciation. In the Upper Quaternary, after the glaciation, the vegetation with Artemisia especially widens because of the man influence: clearing and/or breeding. This plant, which actually gives us many environmental problems, seems to have been differentiated a short time ago. It is a wind-pollinated vegetable, perhaps issued from the Compositae Anthemidae which have an echinulate pollen grain, the spines have been reduced almost to relics by adaptation to the wind dispersion.