[Rockcresses: The Genera Arabis, Boechera and Turritis East of the Cascade Mountains of Oregon and Washington]

Eschscholtz's Hairy Rockcress, Hairy Rockcress, Mountain Rockcress, Pacific Coast Rockcress

Arabis eschscholtziana

Synonyms: Arabis hirsuta, Arabis hirsuta var. eschscholtziana, Arabis hirsuta var. glabrata

The photo above shows a close-up photo of the flowers of eschscholtz'shairy rock cress. The racemes are congested at first, but elongate as the fruits begin to form. The white, cream or slightly pink petals measure 4-9 mm long. Photographed along the north loop road below Fish Lake on the Steens Mt., southeastern Oregon..........June 21, 2004.

Characteristics:

Eschscholtz's hairy rock cress is a biennial or short-lived perennial. One to several simple stems arise from a strong taprot to a height of 100 cm. The lower part of the plant is strongly haired with simple or a few forked hairs, but the herbage is smooth above. The leaves are found primarily on the stems. The basal leaves are oblanceolate or obovate-spatulate with short, winged petioles and entire to serrate margins. The basal leaves are 2-8 cm long. The 5-15 stem leaves are auriculate and sessile, ovate-lanceolate to lanceolate-elliptic, as much as 3 cm wide and 2-12 cm long.

The 4 sepals are 3-5 mm long. The 4 white or creamy petals are 4-9 mm long. The inflorescence is a many-flowered raceme. The seed capsules are long, linear siliques, from 3-8 cm long and 1-2 mm wide. The siliques are erect.

Former Varieties of Arabis hirsuta (both varieties now lumped into Arabis eschscholziana):

Var. glabrata: Petals generally over 5 mm in length. Stem leaves mostly entire. Stigma nearly entire and Siliques 1-1.3 mm wide. Usually found in the mountains, usually not coastal. Found from British Columbia to California.

Var. eschscholtziana: Petals generally over 5 mm in length. Stem leaves (especially lower ones) usually toothed. Stigma lobed and siliques 1.3-2 mm wide. Often along coast and in lower coastal mountains. Found from Alaska to southern Oregon.

Habitat:

Eschscholtz's hairy rock cress is found in forests and forest openings at all elevations.

Range:

Eschscholtz's hairy rock cress is found from the Arctic south through much of North America to California, Arizona, and New Mexico, and as far east as the mid-Atlantic states.

The photo above shows a close-up of the lower leaves of eschscholtz'shairy rock cress. The lower leaves form what appears to be a loose basal cluster of oblanceolate to obovate-spatulate leaves with the blades tapering gradually to a winged petiole. The upper surface of the blade ranges from glabrous to sparsely covered with spreading hairs. Note also the lower stem covered with numerous spreading hairs at the lower right corner of the photo. As seen below, the hairs on the stem soon disappear, so that the upper stem is glabrous.

Eschscholtz's hairy rock cress as seen along the Angel's Rest Trail in the Columbia River Gorge, early May 2005.

The photo above shows the stem leaves of eschscholtz's hairy rck cress. The blades are green rather than glaucous and largely sessile. They may also be somewhat auriculate at the base. The blades have entire margins, and may be ringed with spreading hairs.

Paul Slichter