This is a relative newcomer to my yard this year--I saw some last year, but didn't have time to ID or even pick.
The stems are very sturdy, not round, but more squarish in cross
section. Tiny yellow flowers. It looks almost like a very distant,
really heavy relative of Cleavers/Stickyweed, but isn't at all sticky,
or clinging. Each stem is a single plant, though they may be connected
underground, I didn't dig to fins out yet. I plucked one, and had to
grab it with my fist and really pull!
Edited: I found this one--Ranunculus abortivus L. with lots of common names:
Little leaf buttercup, Small-flower crowfoot, Small-flowered Buttercup, Early ywoodbuttercup , Kidney-leaf buttercup, and other variations of these names.
