Wild oats are just about everywhere I go, growing as weeds by the side of the road.
As far as your average lawn is concerned, I would have liked to know how exactly one could consider that edible?
You probably won't be able to digest the grass in your front lawn, but if you let it go long enough something edible might turn up there. Check in a book first, though.
Not here, unless I am missing something. Here we have several varieties of pine and some oak trees, along with the occasional dogwood trees. Sometimes, rarely, you can find some wild apple trees or blackberry bushes, and the only thing that grows on lawns that might be slightly edible is dandelions -although I have never tried. Since I always get a slight rash whenever I work on the lawn and trimmings, I do not think I should take a chance that dandelions might fare any better in regards to personal health.
More detailed information on exactly how to subsist on pine products might be helpful, however, since I do not know personally anyone who harvests them for eating. Mostly mature trees for the lumber, younger pines for the seasonal Christmas Trees, and pine needles for good firestarting stock.