About Boechera shockleyi (Munz) Dorn
Boechera, commonly called rockcress, is a genus in the plant family Brassicaceae. It is named for Danish botanist Tyge W. Böcher (1909–1983), who studied alpine plants, including the mustards Draba and Boechera holboellii. Recent molecular studies confirm that Boechera is closely related to the genus Arabidopsis, which contains the widely studied model plant Arabidopsis thaliana. Until recently, all members of Boechera were classified within the genus Arabis, but were split from Arabis based on new genetic and cytological data. Unlike Arabis, which has a base chromosome number of x=8, Boechera has a base chromosome number of x=7, and many of its taxa are triploid. Boechera is a mostly North American genus, with the highest diversity in the western United States. Its distribution also extends to Greenland and the Russian Far East. The genus remains understudied, and species are hard to distinguish morphologically, though some clearly distinct species have been identified. Most members of the genus are perennials. They have hairy leaves with stellate trichomes, narrow curved fruits, and small white to purple flowers arranged in elongated racemes. Evolutionary relationships within the genus are not clear; some eastern North American species, such as Boechera laevigata, may belong to a separate clade from the rest of the genus. A notable trait of many Boechera species is asexual reproduction via a process called apomixis. Microsatellite data has shown that some apomictic lineages are hybrids formed from two or more sexual parent species. Ecologically, Boechera species are one of the main food sources for caterpillars of the butterfly Pieris oleracea.
