CARBOHYDRATE METABOLISM AND GROWTH IN EDIBLE CANNA 13 
ing with the mangel, found that during the early stages of growth, 
when leaf formation is the main function, sucrose exceeds the hex- 
oses in the leaves, but that later in the season, when sugar is being 
stored in the root, the hexoses predominate. They further noted 
Fig. 8— Effect of parent stem on offspring. Left, stunted secondary growth with parent stem dead; 
center, upper, first generation roctstcck attached to seed. This small, cylindrical type has only the 
seed to support its growth. Center, lower, two stunted offspring with no parent stem, it having 
been removed several months previous: and right, two vigorous offspring with good parent stem 
Fig. 9.— The progressive changes in shape of rootstocks in the hill. A, original seed with first gener- 
ation cylindrical rootstock attached; B, second generation, small, intermediate type; C, third gen- 
eration, large, intermediate type; D, fourth generation, surface type; E, fifth generation, surface 
type; spike rootstock, partly developed 
that the hexoses always are in excess of sucrose in the midribs and 
stems, and that the ratio of hexoses to sucrose increases rapidly in 
passing down the stem to the root. The hexoses vary greatly dur- 
ing the day and night and throughout the season, whereas the sucrose 
