396 REPORT OF THE CONFERENCE ON GENETICS 
SOME PRACTICAL EXPERIMENTS IN 
CROSS-FERTILISATION IN NEW SOUTH WALES. 
By GrorGe Kersuake, of Sydney, Australia. 
PRoBABLY there are few countries which offer better natural climatic 
advantages for cross-breeding plants than New South Wales. The range 
of subjects that can be grown without the aid of expensive glass 
structures is very large, though at some seasons difficulty is expe- 
rienced in procuring a supply of pollen, on account of the dryness of 
the air and hot winds, which frequently render it impotent in a few 
hours. However, the difficulty is easily overcome by artificial develop- 
ment in a more suitable atmosphere. 
In relating a few incidents in my experience here, I do not know how 
far my methods will agree with those practised in other countries, as in 
a great measure I have been playing a lone hand in this far-off country, 
having few of the advantages of intercourse with those of similar tastes 
and inclinations, which the more populous centres naturally afford. It 
is my intention to only casually refer to a few peculiarities noted 
in connection with some of the popular races of flowers, such as 
the rose, chrysanthemum, dahlia, &¢., which have engaged my attention 
for many years, as in my opinion they offer very few difficulties to any 
intelligent operator. It is when we get off the beaten track of those 
subjects which have been crossed and recrossed for a considerable time, 
that problems so frequently occur which theory may explain. 
But their practical solution is quite another matter, for the simple 
reason that without practical experiment we are ignorant as to whether we 
are working in a grove which nature will respond to, or one which will defy 
our most persistent efforts under all circumstances. A case in point may 
be of interest. A number of blooms of Opuntias were emasculated, and 
as the period is short during which the unopened flower can be safely 
operated upon (about ten hours) before the stigma arrives at the receptive 
stage, a fine jet of water under moderate pressure is directed into the 
flowers, to remove the stamens after being severed, which is rather 
difficult in the immature flower. This method is perfectly safe and 
effective in this dry climate, and is adopted with most Cacti, excepting 
Kpiphyllums and a few others that flower in winter. 
In the case of Opuntia Piccolomini x Cereus Spachianus and of 
O. Piccolomam x Phyllocactus Schlimmii, the union was complete in every 
instance ; while O. elatior and O. senilis, operated upon with the same male 
parents and under the same conditions, resulted in an absolute refusal. A 
certain amount of irritation or swelling of the fruit was noticeable for a 
short time, but neither reached fertility. This behaviour is difficult to 
explain, as the plants were of equal age and had been fruiting regularly 
