Last week the question was: What is this weed?
This is Florida pusley. It is a summer annual with a spreading, prostrate growth habit. It is commonly found in lawns in the South. Seed production occurs quickly after the flowers appear. When found this time of year, the best thing to do is just let the winter kill it and use a pre-emergent broadleaf herbicide in the spring to kill the seedlings as they emerge. Here is a publication with more info.
Here is this week’s question: What is this growing on an old piece of wood?