THE ORCHID REVIEW. 
POLLINATION OF ORCHID FLOWERS. 
F OR many years past there has been a great desire to produce hybrids, 
and, as is well known, the method consists of removing the pollen 
from one flower and transferring it to another. This is called cross¬ 
pollination. It is also used in cases where a typical form of any species is- 
rtquired to be increased by being raised from seed, for it is a comparatively 
easy matter to obtain the necessary pollen from another plant. Some very 
fine forms of Odontoglossum crispum have of late years been raised by 
crossing selected varieties. In fact, the results have been so good that it 
is very doubtful if anyone would again go to the trouble of importing these 
plants from South America. Cattleya aurea has also been raised in England, 
and under cleaner conditions than perhaps exist in its native country. 
But when a new and fine variety, say an albino, is required to be 
increased by seed raising, it is very rarely possible to procure pollen from a 
similar and unrelated plant, consequently the flower must be pollinated 
with its own pollen. In other words, self-pollination is brought about. 
In the case of a plant, such as a Dehdrobium, having several flowers, there 
aie better chances of success, but when only a single flower is available 
then there is no other means of attempting fertilisation than by pollinating 
the individual flower with its own pollen. While cross-pollination nearly" 
always results in effectual fertilisation, self-pollination by no means brings 
about such successful results; in the best cases rarely is more than a small 
quantity of seed produced. The capsule may appear to be full, but an 
examination under a powerful lense will frequently prove that much of the 
enclosed material is valueless, the few perfect seeds being lost unless treated 
with considerable care. The late Mr. Charlesworth found this to be the 
case, and devised special means for sowing the contents of capsules that 
resulted from self-pollinated flowers and obscure crosses. 
Concerning this subject. Dr. A. F. G. Kerr made some notes in 
Northern Siam on Orchids growing naturally, and on specimens removed 
from the neighbouring jungles to his garden for convenience of observation. 
The results are published by the Royal Dublin Society ( Proc. vol. XII. r 
N.S ., No. 5). One of the plants experimented upon was Dendrobium 
pulchellum, Roxb., known in gardens as D. Dalhousieanum. It was found 
that when a flower of this species had its pollinia removed, and placed on 
its own stigma by artificial means, the flower soon withered away, but 
when the pollinia were placed on the stigma of the flower of another plant, 
that flower formed a capsule. Thus, if self-pollination could take place by 
natural means, it would probably be of no benefit to the flower. Seven 
flowers were artificially pollinated; of these six were pollinated with their 
own pollen, and all withered without showing any swelling of the ovary ^ 
