Persicaria maculosa
Similar to Microstegium vimineum (Trin.) A. Camus
Spotted Lady's Thumb or Knotweed, Persicaria maculosa [ Polygonum persicaria ], is a nonnative invasive plant (Significant Threat) also found in low lying, moist areas. It is distinguished from Microstegium by pale to dark pink flower calyx and glossy black seeds.