32 
BULLETIN 57, HAWAII EXPERIMENT STATION 
same field three months later may appear quite young due to its 
profusion of new stalk growth. Two months later still, new root- 
stocks in appreciable numbers may be found growing. This would 
seem to be the order of growth rather than a steady, simultaneous 
growth of rootstock and top. The cyclic tendency is partly masked 
in the results of monthly harvests since growth within the rootstock 
increases the yields regardless of whether new rootstocks develop. 
Previous consideration of the relation of classification to growth 
indicated the contemporaneous appearance of Group 1 with the sud- 
den increases in the new growth of the hill. Moreover, the curve 
for this growth follows very closely the curve for the total number 
of rootstocks in the hill. Whether this is the cause or the effect 
of the new growth is not known, however. Of the three groups, 
Group 2 would naturally be expected to be the most constant and 
Fig. 17.— Cyclic growth of canna plants, 24 months old. Note the vigorous top growth which has 
sprung up as the result of a windstorm which blew down all the old stems. The rootstocks are 
nearly all undersized. 
to show a tendency toward gradual increase as the size of the hill 
increased. This is well exemplified in the two-seed planting. 
The results of Group 3 show little correlation between the irregu- 
lar and the cyclic nature of the new growth of the hill. Unfortunately 
a definite division was not established between the subgroups 3a 
and 3b 4 during the progress of the experiment. Obviously, a group 
comprising all the stages of growth from that of the youngest spike 
up to the mature stage would hardly indicate monthly variations. 
Moreover, after a long dormant period a spike may develop a stalk 
and thus remain in Group 3a much longer than would be the case 
did the stalk develop normally. Apparently Groups 2 and 3 to- 
gether maintain a relatively constant but slowly increasing number 
of rootstocks in the hill, the increase in the total number in the hill 
being largely accounted for in Group 1. 
* Since the completion of this investigation the classification method has been revised, Group 3 being 
further subdivided into Group 3c which includes those rootstocks just emerging from the developing bud 
stage. In addition the number of spikes and stalks are noted in each group. It is belived that these re- 
visions will furnish data concerning the top growth and make the method more responsive to new growth 
in the hill. 
