What is this weed?

Question

This leafy weed spreads very quickly throughout the lawn. The leaves start out green but then turn yellow. They form a dense mat and never rise above a few inches. It seems to die out in the winter, then starts back up at the end of spring. The root is just a long single stalk, so it’s easy to pull up, but it keeps coming back. I don’t want to try any herbicides until I know what this darn thing is. Please help!

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Answer 1

I believe that may be buttonweed. Here is more info on it:
https://aggie-horticulture.tamu.edu/archives/parsons/turf/publications/weed9.html

Answer 2

You are absolutely correct! I identified it last week as Virginia Buttonweed. Thanks for your help!