Some populations in northern Indiana and northern Illinois, [e.g., Herman 8790 (Jo Davies County) and Friesner 19072 (Elkhart County), both at GH] most likely represent hybrids between the two varieties of Arabis pycnocarpa. Trichomes borne proximally on stems of these plants are a mixture of forked and simple. It is expected that hybrids can be found where the ranges of the two taxa overlap.