26 
effect that this change would be brought about if the terminal bud 
be removed during a certain phase of the moon. Some of his trees 
so treated showed the change but others did not. Those treated at 
fairly definitely recurring periods, however, were the specimens 
which appeared to undergo the change. He reached the conclusion 
that other conditions than the loss of the terminal bud must be pres- 
ent, and suggested that the trees may pass through cycles of develop- 
ment and be subject to this change only at certain times. It is a well- 
known fact that merely removing the terminal bud can not be 
depended upon to produce the change. 
The complete change of a male tree to one purely female, with fruits 
of the form of the ordinary dioecious papaya, is perhaps the most 
remarkable. A well authenticated case of this character has been 
reported to the writers and the tree in its present condition has been 
examined. This tree, which is represented in Plate X, figure 1, pro- 
duces pistillate flowers. When examined and photographed on Janu- 
ary 24, 1913, no evidence could be found of any staminate or hermaph- 
rodite flowers, or of any fruits which appeared to have grown from 
the latter. All the branches were producing fruit, except one which 
was too small and weak, being crowded out by the larger members. 
Dr. John T. Gulick, a scientist of wide reputation, whose studies in evo- 
lution published by the Carnegie Institution would alone be sufficient 
to establish his accuracy of observation and statement, has kindly 
furnished this station with the history of this tree,* which has grown 
in his garden. His letter reads as follows : 
Honolulu, May 28, 1913. 
J. E. Higgins, Esq. 
Dear Sir: In reply to your request for the history of the papaya tree that changed 
its habits after being beheaded, I am able to give a few facts. 
When the tree was a year and a half or two years old it had produced only staminate 
flowers, growing on long, dangling branches. It was then 6 or 7 feet high, and as the 
only use we had for it was as a support for a clothesline, we cut off the leaves and the 
top of the tree that were in the way of the hanging clothes. 
It was not till many months later that we noticed that the new branches were bearing 
fruit and that the flowers were all pistillate. During the three years that have passed 
since its head was cut off it has developed 10 branches, some of them being 8 or 9 feet 
in length, and all of them producing pistillate flowers and fruit. The trunk has also 
grown in size till now about 18 inches in diameter. 
Yours, truly, 
(Signed) John T. Gulick. 
It will be seen from the above that no known factor has entered as 
a cause of this change except the removal of the whole top of the tree. 
Why so marked a result should follow such treatment in this case, 
while in many others no change is brought about in the character of 
the flowers, is a question wholly unsettled. The theory of cyclic 
development proposed by Iorns offers a possible hypothesis. The 
