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McDonald's Rock Cress
(Arabis mcdonaldiana )
Mustard Family (Brassicaceae)

A small plant with purple flowers growing in rocks.
BLM Photograph
Purple flowers.
BLM Photograph

Description: This erect perennial herb ranges from 5-15 inches (12.7-38.1 centimeters) tall. McDonald's rock cress has relatively large, conspicuous lavender to purplish flowers (petals are spoon shaped) upon a basal rosette, usually flattened with oblong, toothed, and hairless leaves from which the flowering stems 3.73-11.8 inches (10-30 centimeters) arise.

Distribution: Occurs at a few known sites in Curry County, Oregon, Del Norte County, California, and Mendocino County, California, east of Leggett on BLM's Red Mountain.

Habitat: Occurs on barren to shrub-covered shallow dry ridges, rocky outcrops that are composed of deep reddish soils. Jeffrey pine woodland community at ±3,737 feet (±1,200 meters) in elevation.

Flowering Period: Blooms May through June

Similar Plants: Waldo rock cress (Arabis aculeolata) which is hairy, taller and has wider, less truncated petals than McDonald's rock cress.

Status: Federal Endangered; California State Endangered; California Native Plant

Field Office: Arcata

Last updated: 02-23-2012