mountain rockcress, Arabis eschscholtziana, California, White Mountains, Cottonwood Basin, Fishlake Valley drainage, elevation 3021 m (9910 ft).

One has to get out much earlier than I did to find this mustard in flower. This species, formerly known as Arabis hirsuta var. glabrata, is widespread in northwestern North America, from Alaska and northwestern Canada south to the northern Rocky Mountains, Great Basin, and into Southern California. This location in the White Mountains is about the highest elevation it reaches. It likes mesic sites such as meadows, swales, and rock crevices.

For those following rockcress taxonomy, this is one of a handful of North American species that remain in the largely Eurasian genus Arabis after separation of the North American genus Boechera.