It's called foxtails. Actually several different types of grass awns that can get in doggies, eyes, ears, noses or between their toe pads.
Then they work their way under the skin. It is quite painful to the dog and can be life threatening if left in the dog. So if your dog has been out in the dry grass, check your dog carefully to make sure none are on him/her.
If they are in the dogs eye, you will notice the irritation right away. If they get inhaled into the dog's nose, you should notice that right away too as the dog will sneeze, scratch at it's nose or you might even see a trickle of blood from the nose....
If your dog is shaking his/her head a lot or sitting with it's head titted to one side, it may have a foxtail in it's ear.
So watch out for these if you are outside in long, dry, grass in the California area...