In my post, Sin(s) of Omission I mentioned the weeds I overlooked. Well, it turns out those weeds are Yellow Nutsedge (Cyperus esculentus), considered one of the world's worst weeds.
A Wisconsin field was reported to have up to 35 million yellow nutsedge tubers per acre! The tiny tubers, noted by the small circles on the photo above, are edible when mature (they look like a small nut), and grown in some regions where the starchy tubers are used to make a beverage. The tubers are the primary means of propagation and can live in the soil usually 3 years but up to 10 years. They develop skinny root-like rhizomes 8-24 inches long.
The problems with this weed are several. For one, they compete with crops for water and nutrients. Another problem is they are allelopathic, meaning they produce compounds in the soil that are toxic to some crops. And a third, of course, is that they are invasive.
I think I'll pass on harvesting the tubers for a beverage, and do my best on the eradication process!