Restricted Noxious Weeds 
Agronomy 105's Weed ID
Giant foxtail
Giant foxtail is the only grass on Indiana's list of restricted noxious weeds.  Giant foxtail is closely related to green and yellow foxtail but these two weeds are much smaller and not as damaging as giant foxtail.  It is an annual grass with a very shallow root system. 
If you look at the seed head of giant foxtail you will see that there are 3-6 bristles attached to each seed and the seed head bends over as it matures.  This is a characteristic that can help distinguish giant foxtail from the other foxtails. 
The seed of giant foxtail is light green to yellow and will still have the lemma and palea attached.  Giant foxtail is a very troublesome weed in Indiana soybean and corn fields.  Because it produces so many seeds per plant, it spreads very rapidly if not controlled.  The seeds of Giant foxtail are larger than the seeds of Green and Yellow foxtail.