THE ROOT 175 
ABNORMAL STRUCTURE OF DicotyL Roots.—In certain 
Dicotyl roots as the Beet, Jalap, Pareira, and Poke, after the 
normal bundle system has been formed, there then develop suc- 
cessive circles of cambiums in the cortex outside of these bundles. 
Fic. 107.—Cross section of the daughter tuberous root of Aconitum Napellus, 
Spark’s variety, cut slightly below mid-region. Photomicrograph X 25. ¢p, 
epidermis; fc, primary cortex; en, endodermis; si, sieve strands in inner bark; c, 
cambium; wp, wood parenchyma; xy; tracheary tissue of xylem; m, pith. 
Each of these cuts off phloem on its outer face and xylem on its 
inner face, thus producing concentric series of open collateral 
bundles. 
Hisrotocy or A Dicotyt Tuserous Roor (AconITUM).— 
Transverse sections made through the tuberous roots of Aconitum 
Napellus vary in appearance depending upon the level at which 
