I was trying not to drop this into a non-lawn forum but I’ve found that the community here is the best for such things.
I was under the impression that this beast was a variety of crab grass but now that I’ve gotten to see it mature I am not as sure. It certainly has the radial growth pattern of crab grass, broad leaves, and has those woody “stems” that you see with crabgrass but the seed heads are not what I expected.
I live in the north east with sandy soil if that helps. Its actually sort of pretty once mature but difficult to mow and awful to walk on so it has to go. Any help identifying it is appreciated since it is the first step to taking it down.