Polygonum arenastrum (weed)
From Pestinfo-Wiki

Polygonum arenastrum (click on image to enlarge it)
Author(s): Joseph M. DiTomaso, University of California - Davis
Source: IPM Images
Author(s): Joseph M. DiTomaso, University of California - Davis
Source: IPM Images

Polygonum arenastrum (click on image to enlarge it)
Author(s): Joseph M. DiTomaso, University of California - Davis
Source: IPM Images
Author(s): Joseph M. DiTomaso, University of California - Davis
Source: IPM Images
Polygonum arenastrum (weed) Bor. - (oval-leaf knotweed)
The species is regarded as a subspecies of Polygonum aviculare by some authors.
For details see the respective page in Wikipedia.
Publications covering Polygonum arenastrum (weed)
Weed Technology (2017) 31, 752-760
Mark Hoffmann and Steven A. Fennimore (2017)
A soil probe system to evaluate weed seed survival in soil disinfestation trials
Plant Disease (2008) 92, 1537-1546
Susanne Klose, Husein A. Ajwa, Greg T. Browne, Krishna V. Subbarao, Frank N. Martin, Steve A. Fennimore and Becky B. Westerdahl (2008)
Dose response of weed seeds, plant-parasitic nematodes, and pathogens to twelve rates of metam sodium in a California soil