I think it's fairly unlikely that your plant is F. gracilis, Ginger. It has been spreading eastward across the continent from the southern Great Plains for the past several decades, but I don't *think* it has been confirmed in Florida yet. Even if it has, it wouldn't be common there. F. floridana is pretty common in Florida.
F. floridana will produce multiple stems at times, so that's not necessarily definitive. Can you count how many rows of spikelets there are on each flower head? The spikelets of F. floridana are usually arranged in spiraling rows of 5, while F. gracilis spikelets are usually in rows of 3. I can see 3 rows in your first picture, but am guessing there are a couple of more rows on the back side that can't be seen in the picture?
