I see some clover and some nutgrass, but that's probably not what you're asking about. Where do you live? That may help some people ID the plant.

Did you look at images of the Veronica I suggested? https://weedid.missouri.edu/weedinfo.cfm?weed_id=417

corn speedwell; floral_uk is correct. On LI, the window for most effective post emergent treatment, now, has likely passed. Though some reduction in the next crop, w/Rx now, would likely occur. Don’t miss the upcoming preemergent season this summer - commencing earlier than you would think.

thank you all very much. i have very little, just took a picture of a neighbor who had a lot. I will spot treat with chems or just pull.

I live in central LI, and we have the same weeds, in my backyard. The lawn is a mixture or zoyza and regular grass. last year my husband hand pulled a lot of it, but its back again, taking over.