Northern Prairie Wildlife Research Center
Found in all but extreme southeastern North Dakota, Holboell's rock cress occurs from Quebec to Alberta south to New Mexico and California at elevations up to 11,000 ft.
This plant is biennial or perennial from a tough, persistent base bearing slender taproots. There are usually only one to three stems. Plants are covered with short, appressed hairs. Individual plants can be up to three feet tall, but are usually less than 20 inches tall in North Dakota. Many spoon-shaped, usually toothless leaves about 1-2 inches long are crowded at the stem base, but gradually become fewer and smaller toward the top of the plant. Ten to 50 light purplish-to-pink flowers about 1/4-inch long are crowded along the upper half of the stem. At maturity, flowers form narrow pods (silques) about two inches long that bend downwards. Each pod holds several dozen tiny seeds.
Look for Holboell's rock cress from May to July in native grassland where soils are sandy or gravelly. More plants seem to occur in pastures where cattle grazing pressure is high or moderate. I found no mention of economic uses for these plants.
Holboell's rock cress is a member of the mustard family (Brassicaceae), some of whose 2,500 members have been developed into food plants such as cauliflower, radish, turnip, and rutabaga, as well as many ornamentals. However, other mustards are troublesome weeds. The family gets its name from brassica, the Latin name of the cabbage.
Carl von Linne (Linnaeus), the Swedish father of modern plant taxonomy, named the genus in 1753, purportedly after some mustard found in Arabia. There are about 100 species of Arabis in the north temperate zone. Holboell's rock cress was first described for science in 1828 by Jens Wilken Hornemann (1770-1841), professor of botany at Copenhagen. He dedicated the specific epithet to the eminent Danish ornithologist Carl Peter Holboell (1795-1856).