BULLETIN 56, HAWAII EXPERIMENT STATION 
favorable conditions, but the newly formed rootstocks are very much 
undersize. Grouping the hill according to generations shows that 
the new growth is the result of bud development on all the generations. 
The stunted growth is termed " secondary" in contrast with the 
vigorous "primary", growth starting while the parent rootstock is 
young. (Figs. 11 and 12.) 
A number of more or less distinct stages occur during the growth 
of a hill of canna. The first stage covers the establishment of the 
plant, which often requires as long as three months, during which the 
first two generations 
develop. The root- 
stocks lie almost en- 
tirely beneath the sur- 
face of the ground and 
usually are small and 
comparatively low in 
starch content. The 
second stage is one of 
rapid development of 
new rootstocks (fig. 4) , 
the third, fourth, and 
fifth generations devel- 
oping in quick succes- 
sion. These are of the 
oval-surface type and 
usually are large. 
After these generations 
h a v e developed the 
new growth generally 
declines in vigor, and 
the rootstocks decrease 
in size. The original 
stem dies, and the 
stems of subsequent 
generations become 
less vigorous. With 
the decline in vigor of 
the primary growth, the 
secondary growth be- 
gins, producing smaller rootstocks. The new growth thenceforth 
continues to produce stems of diminishing vigor and rootstocks 
decreasing in size until they ultimately become undesirable for starch 
making. 
These stages of growth are not so apparent at Waimea, Hawaii, 
where the plant seems to be perfectly adapted to both soil and 
climatic conditions. One or more "lines" in the hill may continue 
to produce large primary growth for an indefinite number of genera- 
tions notwithstanding the gradual decrease in the average weight of 
the new rootstocks in the later stages of growth. 
Fig. 3.— A close-up view of the base of a hill 4 months old. As is 
characteristic of the canna plant, the newest growth is mostly on 
top of the ground 
