Effect of 300 ppm extra CO2 on Eastern Purple Cornflower

From the CO2Science Archive: Eastern Purple Coneflower, aka Echinacea purpurea, a flowering perennial, furnishes the active ingredient in some herbal remedies and is a nice late-summer display for our gardens. And getting nicer because in 2007 four experiments showing an extra 300 ppm yielded a remarkable 191.5% increase in plant growth. So if you find echinacea makes you feel better when you are sick, just remember your CO2 helps it feel better all the time.