Mountain Avens or White Dryas (Dryas octopetala) is a alpine and arctic flower of Eurasia. It forms small shrubs, and is a popular flower in rock gardens.

The taxonomic name octopetala derives from the Greek octo (eight) and petalon (petal), referring to the eight petals of the flower.

It has a widespread occurrence throughout mountainous areas where it is generally restricted to limestone outcrops. It occurs in Great Britain in the Pennines (northern England), at two locations in Snowdonia (north Wales), and more widely in the Scottish Highlands; in Ireland it occurs on The Burren and a few other sites. It is widespread in Scandinavia, across northern Russia, and in North America from Alaska south to Colorado in the Rocky Mountains.