On sowing wild oats

Abstract

The awn of the wild oat (Avenafatua L.) twists into a helix on drying and untwists when wetthereby burrowing the seed into the soil. It is suggested that the unusual thick-walled outer eel Is ofthe awn increase in length upon drying. Since they remain attached to inner cells which undergono significant change in length, the awn is twisted into a helix to accommodate the longer outercells.