This tetraploid (2n = 40) is a widely scattered Eurasian annual weed, especially in or near urban areas and cropped land. However, it is not nearly as common in Ky. as the native, scandens. There has been much confusion with scandens var. cristata. Plants known as convolvulus var. subulatum Lej. & Court resemble scandens var. cristata in their relatively large winged calices (F). F. convolvulus differs from scandens (F, FNA 5) in its granular-puberulent calices (versus mostly smooth); its minutely roughened achenes (versus all lustrous); its smaller flowers (up to 3.5-5 (8) mm in fruit versus 4-10 mm), on relatively short pedicels; the usually undeveloped keels on its calices (occasionally up to 0.4-1 mm versus usually 0.5-3 mm). Leaves are difficult to distinguish..