Arabidopsis kamchatica is an amphi-Beringian species that occurs in eastern Siberia, the Russian Far East, Korea, northern China, Japan, Taiwan, boreal Alaska, Aleutian Islands, Canada (Yukon, Northwest Territories, British Columbia, northern Saskatchewan), and south to Washington state in the west. This species is widespread throughout Alaska, except north of the Brooks Range. In Denali, A. kamchatica occurs in scattered sites across the mountainous areas, and is more common south of the Alaska Range crest than to the north.
Kamchatica rockcress is one of the mustard plants traditionally used by Alaskans as a salad green or cooked vegetable (along with Brassica juncea, B. rapa, Barbarea orthoceras, Lepidium densiflorum, and Thlaspi arvense) (Moerman 1998, Schofield 1989).
The related Arabidopsis lyrata subsp. petraea leaves contain glucosinolates and bear trichomes which act as defense mechanisms against insect herbivores; the plant is eaten by many herbivores such as the cabbage white butterfly, Pieris brassicae and Plutella xylostella (Clauss et al. 2006, Sandring 2007).
Plants are monoecious and have bisexual flowers. It is thought that Arabis kamchatica is tetraploid, and its parents are A. lyrata andA. halleri (Wolf et al. 2014). Unlike its parents, which are mainly self-incompatible, it is self-compatible. The related A. lyrata subsp. petraea is known to propagate clonally by rosettes (Gaudeul et al. 2007). It is insect pollinated, with syrphid flies being the most common in a Scandinavian population and small bees being the most effective in a German population (Sandring and Agren 2009). Arabis kamchatica is related to Arabidopsis thaliana, one of the first plant species to have its complete genome sequenced (Koch et al. 1999).
Kamchatica rockcress flowers in early summer (May to June), fruiting shortly after (May to June).
Arabis kamchatica is a short-lived perennial herb with one to several simple or branched stems, growing up to 30 cm tall from a taproot. This species is found along river floodplains, or in other disturbed areas. The basal leaves are in a rosette, up to 6 cm long, lyrate shaped and pinnately cleft with one large terminal ovate lobe. The stem leaves are alternate, attenuate, and do not clasp the stem. The bisexual flowers are in a raceme, compact early in the season and elongating in maturity. The four petals are white (occasionally pink), up to 5.5 mm long. Fruits are siliques, a narrow seedpod, 2-4 cm long 1-2 mm wide, held ascending from the stem. Arabis kamchatica is distinguished from other species of Arabis by the lyrate basal leaves, and not having clasping stem-leaves.