Root system of field bindweed, Convolvulus arvensis. Redrawn from B. F. Kiltz. 1930. J. Amer. Soc. Agron. 22:216-234.

Illustration of field bindweed root system showing both deep vertical and shallow horizontal lateral roots. The vertical roots can reach depths of 20 feet or more. Credit: B. F. Kiltz
Credit: B. F. Kiltz