Scleranthus annuus

About

Scleranthus annuus is a species of flowering plant in the family Caryophyllaceae known by the common names German knotweed and annual knawel. It is native to Europe, Asia, and North Africa, and it is known throughout the rest of the temperate world as an introduced species and a common weed. It grows in many types of habitat, often in disturbed areas.

Summary from Wikipedia