Prostrate spurge

Euphorbia supina

A common weed in newly established lawns or thin lawns, it thrives on harsh, sun-baked sites. I have observed spurge growing in hard compacted soils as well as cracks in sidewalks and asphalt parking lots.
The leaves have a red blotch in the center and reddish stems that ooze a milky sap when broken. It's a vigorous plant that can grow up to three feet in diameter.