Family Rubiaceae

Largeflower Mexican Clover, Largeflower Pusley or Florida snow. I don't know why this is named "large flower" as it is the tiniest flower I have ever seen! It grows in the grass and is only about 1.5 cm big!! 

"Be careful when tip-toeing through the Mexican-clover — the bees are busy collecting nectar from it! Richardia (Mexican-clover) is a flowering plant in the family Rubiaceae (which includes coffee, gardenia, cinchona, sweet woodruff, ixora and noni), native to tropical to warm temperate regions of the Americas. 

They are herbaceous perennial plants. According to the IFAS Assessment of the Status of Non-Native Plants in Florida’s Natural Areas May 2007, this plant is a wildflower considered “Not a problem species”, although if is growing in your turf, you may think otherwise as it is difficult to control." -floridagardener.com