Species composition and biomass of four plant communities were investigated in two coastal polar desert areas in eastern North Greenland, bordering the North East Water Polynya - an ice-free sea area kept open by upwelling - and compared with inland areas in North Greenland. Herb barren, the poorest type, has a species richness of 6 species/m(2), a cover of 0.7 %, and an above-ground biomass of 0.6 g/m(2) (vascular plants). The richest type, Saxifraga oppositifolia snowbed, has 10 species/m(2), 5.0 % cover, and 11.2 g/m(2) biomass. A floristic and Vegetation boundary exists a few kilometres from the coast. The coastal areas bordering the North East Water Polynya had an impoverished flora and Vegetation compared to areas near the ice-covered sea, possibly caused by very low summer temperatures and high frequency of clouds. A new delimitation of the polar deserts of Greenland is proposed on the basis of the number of vascular plant species, the occurrence of species with a specific inland distribution in North Greenland and the dominating life forms. At present the polar desert zone includes only areas within a zone up to ca. 15 km from the outer coast of high arctic Greenland - north of ca. 80 degrees N. Large areas formerly classified as polar deserts in eastern North Greenland, as well as in Washington Land in western North Greenland, are excluded. New floristic data confirm that Greenland is correctly included in the Canadian province of the arctic polar deserts, whereas there is no reason for subdividing the polar deserts of the Canadian province.
