Cat's Claw Sensitive Brier
Schrania nuttallii (alternate)
I was not surprised in the least to see this as part of the Mimosa genus (the filamental stamen, and leaf shape are very similar to the bloom of the Mimosa tree. What is surprising is that this bloom (a true "ball" by contrast to the Mimosa "fan") grows on a ground hugging pricker vine, much different than the big Mimosa tree.
Most Surprising, this really is a sensitive brier. While moving a sample of the vine to white card-stock (3rd image) the fronds all closed up. I had to wait some ten minutes for some of the fronds to re-open.