Please could you try to find an example that hasn’t been chopped off and also state your geographical location.

It looks like the wheat straw you put down with the grass seed was also full of seed that germinated with the lawn grass seed. The wheat straw seed is an annual. Just mow it and ignore it. It won't come back next year if you don't let it go to seed.

I'm in SW Virginia. it was recently mowed. thanks so much folks!

We had straw when the yard was seeded and they might not have gotten all of the seed out of the straw.