Awn

Awn, a bristle-like appendage to the glume, or bract, in some grasses, such as oat, barley, bearded wheat, etc. It springs either from the back or from the apex of the glume, and is believed to correspond structurally to the blade of a leaf. It serves to protect the seed from the depredations of birds, and may in some cases assist in burying it beyond the reach of drought.