Pallas' wallflower is a small flowering plant in the mustard family (Brassicaceae) that grows in dry gravelly tundra, calcareous rubble slopes and screes. It has basal rosettes of leaves growing from a thick taproot. Leaves are linear to oblong, with entire or irregularly toothed grayish margins. Flowering stems are very short, elongating substantially when in fruit, up to 20 cm tall. Flowers are bisexual with four purple or pink petals, 1-2 cm long, with claw equal to sepals. The clusters of purplish flowers borne low to the ground mature into elongated, sometimes curved, narrow siliques 3-9 cm long cm long, held ascending from the stem. Pallas' wallflower is the only species in Denali with a cluster of four-petalled purple flowers and linear leaves. It also has distinctive two-parted hairs attached at the middle, which is diagnostic of the genus Erysimum.
Erysimum pallasii flowers early (June in central Alaska's mountains).
This species is monoecious with bisexual flowers. It has been speculated that it reproduces via apomixis, as it fruits abundantly but is little visited by insects. No studies of the reproductive biology have been done on Erysimum pallasii. The seeds are dispersed by gravity and water.
Erysimum pallasii has a wide-ranging amphi-Beringian distribution. Indeed, E. pallasii is nearly circumpolar, occurring from northern Greenland across arctic Canada and Alaska to the Ural Mountains in the west (where it is rare) but is absent from Europe. It is common in arctic Alaska, but rare in the subarctic mountain ranges of the state, where it is frequently associated with calcareous bedrock units. In Denali, E. pallasii is rare, restricted to isolated sites in the hills and mountains of the northeastern quadrant of the park.
This is an alpine species with a minimum elevation station of 1006 m and maximum observed elevation of 1572 m in Denali (average elevation across 14 localities = 1186 m). Usually found in scree and fellfields.
Porsild and Cody (1980) describe the species as 'a pronounced dung-loving calciphile', and it does appear to be strongly associated with calcareous substrates in Denali and Wrangell-St. Elias National Parks in central Alaska.
Well-drained dry to moist sites.
Considered rare in Denali National Park and Preserve.