This weed is growing in southern Indiana and seems to spread either underground or by seed, although I have never seen any blooms or seed on it. It is trying to take over an area in my garden where I have some coreopsis growing. I will probably have to get rid of the coreopsis to get rid of the weed.
It has a very thin stem and elongated leaves. It usually doesn't stand up erect, but rather lays on top of other plants.
