The attached is a picture of a weed/grass that is in hay bought from Walden, CO this year. In some bales there is a lot of it and others not so much. I would like to know what it is. I've looked through Colorado grasses and cannot find it. I am pulling it out of my hay as it is pretty stemmy. The horses will eat it, but tend to leave it until the rest of their portion is gone. Also, it makes me sneeze when there is a lot of it in a bale. Thank you for any information you can provide.
Jackson County Colorado
Identifying grasses often requires microscopic examination of some small morphological features.
But a guess, with about 85% confidence, is Jungle-rice (Echinochloa colona). This is a warm-season annual grass that reaches 2-3 feet tall. Look for some purplish bands or stripes on leaves (blades); presence confirms Jungle-rice but absence does not mean that it isn't Jungle-rice.