Please help me. I found this in Toronto, in August this year. Downtown, on someone’s lawn.
Thank you for contacting the Toronto Master Gardeners concerning your plant identification.
Even though your image is quite blurry I believe that the plant in question is snow-in-summer (Cerastium tomentosum).
This beautiful perennial groundcover is a member of the carnation family and gets its name form the beautiful white flower display it puts on in early summer. However, the flowers are not the only show stopper of this plant, it is also admired for its delicate woolly silver leaves.
This plant spreads quickly by reseeding and by producing runners when grown in favorable conditions and makes an excellent groundcover for a dry full sun ( 6+hrs) area. This plant grows best in well-draining slightly acidic (6.0-7.0) soil but it is adaptable to most soils except damp and poor draining soils.
This website gives more information on this lovely groundcover.