Foxtail (diaspore) in the context of "Awn (botany)"

An awn is a hairy or bristle-like growth on a plant.

On the seeds of grasses such as barley or rye, they form foxtails which assist seed dispersal by being barbed and so sticking to passing animals. Also, the awns may twist or curl as they are wetted and dry out and this action can make fallen seeds walk until they fall into a crevice into which they then burrow.