Aoi^ICUbTUHflli 
COLOMBO- 
Added as a Smlenieitt Monthly to the TBOPIGAL AGRICULTUFJST." 
May :— 
The following pages include the Contents of the JgricuUural Mafjazine for 
Vol. XIV.] 
M^Y, 1903. 
[No. 11. 
THE CHANGING OF THE SEX IN PLANTS. 
HE Journal cV Agriculture Tropicale 
avers that the inhabitants of the 
Southern oases in Algeria claim 
the ability to change the sex of 
date palms. 01 100 date palms 
80 are male tiees, heuce it may 
readily be conceived that it is greatly to man's 
i'uterest that the cultivator's intervention should 
be crowued with success. The method consists 
of tearing off all the leaves from the foot- 
stalks at two or three years of age, so that the 
medial nerve is split in two from the centre to 
tlie leaf sheaf. The idea of the Arabs is that 
this tearing process brings on a concentration 
of the sap movement in the same way as in 
the case of au annular incision, and results 
ia an accumulation of sap, which is more necessary 
for the vital functions of the female plant than 
for tlioio of the male. No objection, says the 
editor, from a vegetable pathological point of view, 
can be raised ogaiHst the above assertioL', for 
tlte reason that in youug plants the organs are 
not yet different from each other. 
In our experience, the topping — or cutting 
of the terminal bud — of "male" papaw trees 
{Carica Papaya) as soon as the character of the 
flower is ascertainable, results in altering that 
chaTacter and inducing them to yield good fruit 
in lieu of the wretched specimens borne by the 
«o-called male tree, 
In this case as with the date palms there is 
no doubt that the drastic treatment adopted 
results in what is referred to in the Journal d' Ayri- 
cuUurc Tropicale as a " concentration of the sap. ' 
In the Papaw tJie wenkly nature of the male tree 
is characteristic, and the sex could almost be 
anticipated before blossoming. Wliather any such 
distinctive physical character is observable in the 
date palm we cannot say, but it is more than 
likely there is. By cutting back, therefore, it 
is reasonable to suppose that the sudden checking 
of the upward flow of sap to meet the demands 
of the new growtiis in the region of the ter- 
minial bud, brings about a turgid condition of 
the cells and a corresponding concentrated or 
vigorous condition of the cell-sap, which is 
thus enabled to develope the frui' -bearing organs 
cf the flower. 
In a "male" or staminate flower, we must 
of course assume that the pistillate part of it 
is only suppressed and capable of developement 
under extraordinary conditions. Suppression is 
defined iu botanical text-books as the absence 
of parts in a flower, which, from analogy, we 
might expect to find. The correctness of this 
view is proved by the fact that we often And 
an imperfect or partial developement of organs 
that should be present under ordinary circum- 
stances. To such partial developement of the 
pistil must be attributed the production of im- 
perfect fruit, on the so-called male papaw tree. 
And that the further developement of organs, 
which have a tendency to suppression, is possible 
by artificial means, is further proved by the fact 
referred to above, namely, that the cutting back 
of the plant in the male papaw results in the 
production of pistillate flowers. It will be fouiul 
in actual practice tlHit due cutting back does 
not aljvays bri'n^ about the desired result, and 
that the tree has to bo attacked more than once 
before the tendency to suppression of the fern tlci 
or^jan is overcome, « 
