Looks like annual bluegrass complete with seedheads. Make sure your bermuda is completely dormant before you use round-up. Try using a dabber and saturate the bluegrass without getting it on the bermuda. With the seed production of the bluegrass, make sure you use some sort of crabgrass control throughought the season. Even go longer into the fall. That's is when the seed will germinate is in the fall. Annual bluegrass is a biennial. Germ in the fall, over winter, and grow and florece in the spring.

I am also including a link to a ginseng hunting forum where I have a picture of the roots... The post is titled: 'Question: Have I Found Ginseng???' ---third post down. I think you have to sign up to view messages though. Here is a link that might be useful: Ginseng Forum

Three down, one to go......I asked for help from a local gardening group and was able to get all but one of my "unknown" weeds identified. Number #2 has been sucessfully identfied as GARLIC MUSTARD Number #3 is PRICKLY LETTUCE (thanks jean001) Number #4 isnt even a weed....its a BLACK LOCUST TREE

Dogs often eat plants BECAUSE they're sick. You shouldn't wait on the opinions from the occasional visitor to a forum. Get your dog to a vet if the symptoms continue.