I think it may be

Calyptocarpus vialis

Carol provided the correct ID. You must have had rain, because the normal flowering period is June - August. Straggler Daisy is one of our smallest composites. It is most often found in Texas, growing in lawns and disturbed ground. The BONAP distribution map is available from this link.

Blakrab, I've noticed in past requests that you are assiduous about counting the number of petals on flowers. This is a good identifier on certain genera, such as Brassicaceae but often it is not decisive. On Asteraceae it isn't.