This weed just came up in my yard in South Jersey in the past week.

I know for a fact that it is NOT crabgrass or nutgrass. Can anyone
identify it?

http://www.bookac.com/Images/weeds1.jpg
http://www.bookac.com/Images/weeds2.jpg

The weed only shows up in one of my side yards. Ortho effectively
kills it. I am just curious as to what it is. Thanks!