I walk a lot. I'm noticing this stuff on lawns all over the city. I have it too.
Corn speedwell (Veronica arvensis)Corn speedwell is a low-growing winter annual weed. Upper leaves are small and taper to a point, whereas lower leaves are rounded and lobed. Stems have an upright growth habit and do not spread more than an inch or two from the crown. Plants are covered with sparse, fine hairs. The plant's most notable features are the small blue flowers that grow in the leaf axils and its heart-shaped seed capsules. This weed grows in thin turf during cool weather.
Here's how to get rid of it:
Post emergence control: 2,4-D + MCPP + dicamba,or 2,4-D + triclopyr. Spring or summer. Extremely difficult to control; repeat applications may be necessary.
Preemergence control: Oxidiazon. Late summer. Apply in August before weeds germinate.
Source:
http://turfgrassmanagement.psu.edu/weedmgmt.cfm
