Looks like nutsedge. I usually just pluck them out by hand although there are sprays if you have a lot.

Nutsedge. Pulling actually encourages new growth from underground tubers. You want a sedge specific herbicide that can move through their shared root system. Whether to spot spray or blanket spray is up to you, but the products aren't hard to find at your local box store, ace hardware, or nursery

Thanks reekjake. I'm going to see if they have any in a RTU spray... i've been plucking them every year in the same spots (like a fool).

reeljake: you guys sure it is nutsedge and that it will grow more if you pluck them out? I had something that looks very similar in a particular spot in the back and I just kept hand picking them out. That was a couple of years ago and I have very few now. They pull out very easily and it looks like a complete root cluster or clump when I do so. I don't see anything that looks like rhizomes or tubers.

Forgot about nutlets. Here is a good quick overview. Do you have triangular stems?

http://www.domyownpestcontrol.com/nutsedge-identification-guide-a-561.html

Thanks all. While I am mowing high, I think a fungus outbreak I have almost beat thinned out the parts of my lawn where this sedge is growing. It is prime conditions here in the heat of mid-summer for this to grow. They are just few enough in numbers to pull, but i would rather treat the root system the right way.

It looks your entire lawn is what I know as nutgrass?

Ortho has an RTU spray for nutsedge which comes in a hose-end sprayer. It is the newer sulfur-based formula and should kill the nuts.