From the CO2Science Archive: Eleusine indica (L.) Gaertn. aka goosegrass, Indian goosegrass, silver crabgrass, yard grass, wiregrass, crowfootgrass and perhaps more, is a weed that thrives in hot places especially in sites with disturbed soil like farmland. It is related to millet and its seeds are apparently edible but its yields are low so when it appears farmers are mainly interested in getting rid of it so they can grow something better. Alas this hardy pest benefits from extra CO2. From 1984 to 2006 there were six experiments showing a 34 percent growth boost from an additional 300 ppm CO2 and a 48.5 percent growth boost from an additional 600 ppm CO2. So if Indian goosegrass is not to your taste you better get rid of it as soon as it starts to grow because each plant can produce 50,000 seeds when mature.