Can anyone identify this grass?
It is either yellow or purple nutsedge. There's a little difference in the color of the tassle on top and one grows a little taller if I remember correctly, but essentially the same.
Nutsedge spreads by underground runners as well as the tubers which resemble small peanuts, which is where it gets the common name. Tenacity is the best control. It is shallow rooted and reasonably easy to pull up if the ground is moist and soft- unless there are a lot of other grass, etc. roots that help hold it in place. There are a few products (Image is one) that is supposed to control nutsedge without harming the lawn. They are expensive, around $30 for a pint the last time I got some. If you use it around flowers it will kill them also just as if you used glyphosate (RoundUp) but it can serve a purpose with treating the nutsedge in the lawn where other methods could be disfiguring.
There is some research that indicates nutsedge knows when you use herbicides and dislodges the tubers before the herbicide can destroy them. That seems to make sense based on my experience with it coming back repeatedly.
If you pull it, spray it or whatever and watch for the little ones to come back- they will! and then pull them out while they are still small and immature, you will eventually win. Eventually!
If it's worth doing, it's worth doing right. If you wouldn't put your name on it, it ain't done right!