I grew up in suburban Pennsylvania. Thus for me, grass is a green lawn. This lawn isn't in Pennsylvania, it's in New Jersey, and it's not someone's lawn, it's a public park, but it's my prototypical image of grass:
But this is grass as well, and in New Jersey too. It's grass of an entirely different character:
Is this grass? One kind or several?
Here you almost can't tell the grass for the trees:
Nor is grass always green:
This grass grows every which way:
As does this very different grass – notice the dew?
This grass glows in the sun:
This grass also catches the sun, and perhaps toss it to the graffiti behind: