[freejohn]

I just over-seeded last week.
Will the Ortho hurt the seed?

[DaveTesla]

Don't spray the whole lawn.
Use the premix with a spray nozzle.
Spray it on the leaves of the weeds.
Aim at center of the weed.
Spraying while warm (<90F) and sunny
always worked best for me.

[tubebender]

Do you think this infestation was in the lawn seed? If it is Oxalis you may be about to spray it and at this stage I would not worry about the grass. Oxalis generally sprouts from little nuts or corms that form at the root level of the plant. Try digging a couple of plants up with a trowel and look for the beginnings of those little suckers. The photo you posted at the start of the thread appeared to show runners spreading out from the plant and that is what I based my ID as Burr Clover...

[DaveTesla]

black medic

It's the flowers that had me confused....

Doesn't matter,the Ortho will kill it.

http://weeds.cropsci.illinois.edu/images/Black%20medic/pages/black%20medic1.htm

http://www.google.com/search?q=Black+Medic