Not sure what this is. Reminds me a little of liriope (monkey grass) but the stems are not as rigid. They also have a purplish hue along the edges and more toward the inside of the stems where they all meet together. Roots are very similar to lirope and mondo grass.
We have mondo grass in our yard and this isn't the same thing. It's a lot taller. I know there are so many different kinds of grasses. This doesn't seem to spread as quickly as the mondo grass we have or as fast as the regular variety of monkey grass we also have gobs of.