Grass type is easy to identify even just with a Google image search. But as far as identifying the specific cultivar, you'd probably need some sort of DNA test for that one.

Thanks lawniac. Well I won't say it's easy by Google. As clean, close up pictures are rare. And I see same picture labeled as different grass at different sites. So not accurate to say the least. For instance I'm trying to identify following two grasses

one is short leaves other has long leaves. one is denser than other and little lighter in color.

I failed to find any picture on google that is properly labeled with the grass name and positively matches either of these pictures.

I'm not sure if this might help it might rule out what its not

http://turfid.ncsu.edu/ItemID.aspx?orderID=GR&orderDesc=Grass

Thanks gappsxr. checked out all the grass listed. didn't find a match.

characteristic wise it match the bermuda grass, except blades are away more wider.

looks wise it match crab grass, except shorter length blades and doesn't spread from one point outward (which is signature for crabgrass).