Atriplex are C-plants, with a characteristic leaf anatomy (kranz anatomy). The genus "Atriplex" is distributed nearly worldwide from subtropical to temperate and to subarctic regions. Most species-rich are Australia, North America, South America and Eurasia. Many species are halophytes and are adapted to dry environments with salty soils. The genus evolved in Middle Miocene, the C-photosynthesis pathway developed about 14.1-10.9 million years ago, when the climate became increasingly dry. The genus diversified rapidly and spread over the continents. The C"Atriplex" colonized North America probably from Eurasia during the Middle/Late Miocene, about 9.8-8.8 million years ago, and later spread to South America.
Wrangell–St. Elias National Park and Preserve spruce are better adapted to fire conditions. Both quaking aspen and paper birch are common deciduous species that are among the first trees to grow following a fire. They are followed by balsam poplar and eventually white spruce. Subalpine environments occur above the local tree line, which in Wrangell–St. Elias usually varies from to . Plants are low and slow-growing shrubs, mainly graminoids and forbs. The alpine environment is variable according to the availability of water. It starts at a variable altitude from in dry areas to in wetter areas. Heaths and low-growing willows are common, along with forbs. Large