Mystery Plant and Baby Pics

I was out in the backyard a day or two ago when I noticed the ground was different - in an area that had been kind of mud colored, there was a sea of green sprouts:I don't know what it is, but whatever it is, we have A LOT of it. It absolutely carpets the backyard. It is not grass. I was wondering if it might be milkweed, because I have some plants in the corner that had pods burst, but this seems excessive.

Awe, even baby plants are cute :)

And here is my sweet baby:I think Annalise took this picture. She likes to take pictures sometimes, but they usually aren't this well centered :)