Could you take a picture of the plant growing in the lawn? And a close-up of the seed head?

Ugh, looks like Bahiagrass. After mowing, makes 12-18" stalks of ripe seeds within days. Awful stuff that I hate even with my "whatever's green is fine" attitude for our mowed areas. I've been pulling the giant rhizomes (that simply squash/smash the regular grass to death) out of areas where we usually walk. Nobody likes having those seeds stuck all over them from the knees down. If not for that stuff, going 3-4 weeks sometimes (when it doesn't rain) between mows would be fine for the regular grass.

Bahia has a very distinctive two-pronged seed head; it never varies.

The picture looks like the seed head of.......Centipede grass! This is the time of year that this grass species looks 'hairy ' no matter what you do. There's a myth that centipede doesn't create seed (and ugly seedheads), but it does.

You're right, I obviously glanced too quickly, with that awful stuff on my mind (and my hands.)