abstract:Dryas octopetala (common names include mountain avens, white dryas, and white dryad) is an arctic-alpine flowering plant in the family Rosaceae. It is a small prostrate evergreen subshrub forming large colonies.
The episode is known as the Younger Dryas, because in Scandinavia abundant pollen from a tundra flower called the mountain avens, Dryasoctopetala, reappears in soil from this date, indicating that the forest had once more given way to tundra.