Identifying a lawn weed
Hi - This looks like a type of buttercup (Ranunculus sp.). The bulbous buttercup is the type most commonly found in lawns and there is also a very similar species, creeping buttercup, which stays low to the ground as it spreads. https://www.oardc.ohio-state.edu/weedguide/single_weed.php?id=17
Here is our page with information on how to deal with buttercup in a lawn,
Buttercups tend to show up in lawns with low fertility soil. If you plan to renovate the area where these weeds are located, begin by getting your soil tested to check the pH and nutrient levels. The optimal soil pH should be between 6.0 to 6.8. Here is our information about how to do a soil test, https://extension.umd.edu/hgic/topics/soil-testing
When a lawn area is 50%+ weeds, we typically recommend a complete renovation. Your best defense against weeds in general will be to grow a dense stand of healthy turfgrass. On our website, we have a step-by-step guide to renovating a lawn, https://extension.umd.edu/hgic/topics/lawn-renovation-and-overseeding
Thanks so much for that info Christa!
You are welcome!