Dear Barb,

Thank you for contacting us for identification of the plant in your yard. I am reasonably sure the plant is not creeping buttercup, and more inclined to say it is in the geranium family (Geraniaceae). In this case, unfortunately, the dark splotches are not particularly helpful for identification.

Creeping buttercup (Ranunculus) is a perennial with creeping stems (stolons) that spread across the ground. New plants grow from the rooted stems. The flowers are generally yellow. Geraniums, on the other hand, spread mainly from seeds with flowers that are often pink through blue or purple. 

It would be helpful if you could give me the flower color (if you recall from last year), or a description and photo of the root. Also, verify whether there is any stems that connect the separate plants. As you probably know, the difference between a 'weed' and a plant is determined by whether you want it. That being said, buttercup is a very aggressive plant that can take over a large area and would not be desirable. 

I hope this information is helpful. Feel free to reply to this email if you have the additional information or questions.