I've got a weed I am trying to identify that is growing among my St. Augustine grass. The weed never seems to grow large (like crabgrass). It is intermixed with my grass. Picture attached. I can't seem to identify it using the numerous weed galleries out there. It seems to have 'runners', like St. Augustine, and grows in patches (mixed with St. Augustine).

Thanks in advance.

For assistance with ID, take a good-sized sample to a local large independent garden center or to your county's Extension Serivce office.