126 



SCIENCE 



[N. S. Vol. XXVIII. No. 708 



are sometimes perfect, but such have not come 

 under my notice as yet. 



The. fruit varies in form from oval to a 

 distinctively necked pear shape and in weight 

 from three pounds to ten povm^ds or even more. 

 The fruit in some varieties is very delicious 

 and has many medicinal properties ascribed 

 to it, so that the plant is of enough value 

 economically aside from its botanical interest 

 to be worthy of careful study. 



The change of sex in the first tree noted 

 was brought about accidentally. A staminate 

 tree of some age had its terminal bud acci- 

 dentally injured. The staminate flower clus- 

 ters produced shortly afterwards contained 

 pistillate flowers in the terminal group. These 

 flowers set and developed good-sized fruits. 

 When mature they had all the characteristics 

 of normal fruits except that the fruits were 

 not quite so well filled out, having a somewhat 

 wrinkled appearance. The seeds are smaller 

 than the normal seeds but seem to be normal 

 in other respects. Time has not been suffi- 

 cient to test their germinating power. The 

 clusters later developing also contain pistillate 

 flowers in the same position in the cluster as 

 the first one, and now and then a cluster will 

 contain two and even three of these fertile 

 flowers, each one producing fruit. 



On observing this peculiarity, investigations 

 were begun to find the cause. Inquiry of the 

 natives brought out the theory that the re- 

 moval of the terminal bud in the new of the 

 moon would usually cause this transforma- 

 tion. Other trees growing on the grounds 

 were at once set aside for experimental pur- 

 poses and the tops were removed at different 

 phases of the moon to disprove the moon's 

 having any effect and also to show, if possible, 

 what were the necessary conditions, if any, 

 outside of the mere removal of the terminal 

 bud. Thus far it is clearly shown that the 

 removal of the terminal bud does cause the 

 change, but also that some other condition is 

 necessary, as only a part of those thus treated 

 have thus far developed any pistillate flowers. 

 The moon's phase does not appear to have any 

 control, though, strange to say, those treated 

 at a fairly definitely recurring period are the 

 ones that show change. It is possible that the 



plant has definite short cyclic periods of 

 growth and that it is necessary to remove the 

 tip at some definite phase of this cycle in 

 order to produce the development of fertile 

 flowers. If this be true and this cycle should 

 accidentally coincide fairly well with the 

 moon's phases, the belief in moon influence 

 would naturally arise. 



This view of an approximately monthly 

 periodic cycle of growth has several things to 

 support it. The chief of these is found in 

 the continuous development of flowers and 

 fruit. At no time during the year were the 

 trees under observation without both flower 

 and fruit. On the other hand, there are times 

 when growth is more rapid, more flowers are 

 developed and the terminal nodes elongate 

 much more rapidly. The exact time of these 

 periods has not yet been determined definitely, 

 but data is being collected. 



The habit of the plant is being closely 

 studied to determine the characteristics of 

 each change and at what point in this growth 

 the tips must be removed to produce the 

 changes under discussion. It is possible that 

 the power to produce pistillate flowers is in- 

 herent in the plant, being dormant unless some 

 shock is given to destroy the equilibrium of 

 the growth forces. This inherent quality is 

 indicated by the fact that in some countries 

 the plants are sometimes found naturally 

 monoBcious.' 



It may also be that certain varieties are 

 monoecious. That there are variations in the 

 plants is true, as noted under forms of fruits, 

 but thus far no variation has been observed 

 that was definite enough or of well enough 

 fixed characters to warrant a well-defined divi- 

 sion into varieties. 



I recognize that as yet but little has been 

 definitely settled and that the questions in- 

 volved open up a wide field for investigation, 

 but I present the facts, thinking they will be 

 of interest and hoping that any discussion 

 caused by them will bring out points that will 

 aid in future investigations. 



M. J. lORNS 



Matagtjez, Poeto Rico 



^ " Dictionary of Economic Products of India," 

 Watt, Vol. II. 



