In 2013, the New Ornamentals Society (now Cultivar.org) set about to update it's extensive files on flowering maples or Abutilon. More than 110 cultivars were described. We expected the project to yield perhaps 200-300 cultivars and be finished in six months. It turns out that this genus was far more popular in modern times and a century ago than any of the researchers realized. After nearly two years, a descriptive checklists of 525 cultivars came together to the surprise of all involved. We dug even deeper and found new images from gardens and historical scans of old catalogs that sometimes had informative illustrations. This volume is, we believe, the most complete study of the garden varieties of Abutilon ever compiled and is the product of hundreds of hours of study and travel.