[The Genus Arabis East of the Cascade Mts. of Oregon and Washington]

Sicklepod Rockcress

Arabis sparsiflora

Arabis sparsiflora var. atrorubens

Photo above of Arabis sparsiflora var. atrorubens from the Little Spokane River Natural Area...........May 6, 2012.


Characteristics:

Sicklepod rockcress is a biennial or short-lived perennial with one to several upright, simple to branched stems arising 40-80 cm from a mass of basal leaves. Plants are densely hairy below with simple to branched, star-shaped hairs. The numerous basal leaves are oblanceolate in shape, 2 to 9 cm in length and 2 to 8 mm wide. The margins are entire to several-toothed and the blades are finely to coarsely haired. The basal leaves narrow to a slender petiole. There are also numerous stem leaves, reduced in size up the stem. The lower leaves are petiolate, but the upper ones become somewhat clasping or auriculate and somewhat glabrous in texture. The stem leaves are linear-lanceolate to oblanceolate in shape, with mostly entire margins.

The infloresence is a long, loose raceme of many flowers. The 4 petals may be white to deep purple and measure 6-14 mm in length. The pedicels are glabrous to sparsely covered with branched, radiate hairs. The sepals are often purplish, covered with branched, radiate hairs, and measure 4-6 mm long. The seed capsules are siliques, long and thin, somewhat flattened, usually arched in outline, and either ascending to spreading-drooping. The capsules are glabrous and measure from 6-10 cm long and 1.75-2.5 mm wide.
Pacific Northwest Varieties:

var. atrorubens: Petals a deep purple color. Siliques ascend. Basal leaves toothed. Pedicels of the flowers and siliques typically not haired. Found east of the Washington Cascades from Chelan County to Klickitat County in the south.

var. sparsiflora: Petals white, pink, or light purplish, but lighter than variety atrorubens. Basal leaves entire margined. Pedicels of the flowers and siliques usually ascending, smooth, and hairless. Found in the eastern part of the species' range from Idaho to Utah, west to southeast Oregon, and south to northeastern California.

var. subvillosa: Petals white, pink, or light purplish, but lighter than variety atrorubens. Siliques usually spreading to descending. Basal leaves toothed. Pedicels of the flowers and siliques usually noticebly lightly haired and spreading. Found from central Washington south to California along the east base of the Cascade Range, and east to Montana and Wyoming.


Habitat:

Sicklepod rockcress is found in arid, sagebrush and ponderosa pine habitats.


Range:

Sicklepod rockcress is found from British Columbia south along the eastern edge of the Cascade Range to California, and eastward to Alberta, and south through Montana, Wyoming and into Utah.


Paul Slichter