This is one of the weedy members of the Mallow family. Most mallows are erect perennial plants with large flowers, while Common Mallow is an annual vine with average-sized flowers. In open areas, it tends to form a mat of leaves and stems across the ground that can extend several feet. It has a similar appearance to another introduced species, Malva rotundifolia
(Dwarf Mallow). The Dwarf Mallow has smaller flower petals that are only slightly larger than the lobes of the calyx, while the flower petals of the Common Mallow are twice the length of the calyx lobes. The Dwarf Mallow is less common in Illinois.