Hop Clover

I seem to be currently taking photos of all sorts of small wildflowers that I see while we're walking. There's a lot of this stuff along the road and in the hayfield. Apparently it's hop clover. My wildflower bible - Peterson's Guide to Wildflowers - says there are three hop clovers: Hop Clover; Smaller Hop Clover; and Least Hop Clover. On our walk I see some that is very low growing (see extra), and then other (this one) that is a bit taller. In any case - it is an "alien" but it's definitely gone native.