a top view of alternanthera philoxeroides, commonly referred to as alligator weed

plant flower wildflower green herb leaf shrub produce nature grass blossom meadow food garden lawn tree alternanthera philoxeroides commonly referred alligator weed small white papery flowers short stalks leaves pairs hollow stems perennial grows land damp soil water dense floating mats establish semi-aquatic areas wetlands stream creek banks close top view white petals