Comparative ozone responses of cutleaf coneflowers (Rudbeckia laciniata var. digitata, var. ampla) from Rocky Mountain and Great Smoky Mountains National Parks, USA

Foliar stipple on cutleaf coneflower (Rudbeckia laciniata L.) var. ampla (a, b) and var. digitata (c, d) on August 10, 2011 after growing outdoors at Appalachian State University, Boone, NC USA. Both varieties have an absence of injury on abaxial surfaces, which is consistent with ozone exposure symptoms. Note blue/black stipple on var. ampla, characteristic of that seen on leaves of this variety in Rocky Mountain National Park, whereas stippling is initially purple/brown on var. digitata and then quickly coalesces into brown necrotic areas.216