494. APPENDIX. 
sionally produce three cotyledons, and subsequently single flowers. He 
has never observed a double flower under these circumstances, though 
it is true his experience in this matter has been but small. 
A writer in Otto’s ‘ Gartenzeitung,’ considers that double flowers are 
a consequence of dryness of soil and atmosphere, and not of a luxurious 
soil, rich in nutritious matter, having arrived at this conclusion from an 
observation of the following circumstances : 
“Fifty years ago we saw Kerria japonica in a hothouse with single 
flowers. Twenty years later we met with it in several gardens, in the 
open air, but always with double flowers. At this time we were 
assured that single-flowered plants were no more to be found in the 
whole of Europe, and botanists forming herbaria offered considerable 
sums for a branch of K. japonica with single flowers. We were requested 
to take the plant in hand for the purpose of inducing it to produce 
single flowers. We were advised to plant it out in a rich soil, which 
was done, but, by chance, the situation was sloping, consequently it did 
not retain moisture, and all the flowers produced for several years in 
succession were double. Shortly after, the captain of an English ship 
again brought plants bearing normal flowers from Japan, which were soon 
spread over the continent, and of which we received one plant. After 
three years all the young plants raised from cuttings were double- 
flowered. 
“Tn the year 1820 we several times visited a garden in the neighbour- 
hood of Vienna, well known on account of its plant culture. The 
gardener there possessed an immense plant of Caimellia japonica with 
single flowers, and some small plants raised from this by cuttings, but 
no other variety of camellia. He fertilised the flowers with their own 
pollen, harvested seeds, which he sowed, and the plants raised from them 
were placed in an extremely dry, lofty conservatory, where, after some 
years, instead of producing single flowers, they all produced double 
' ones. The seedlings and mother plant were planted in one and the same 
kind of earth, and some of the flowers on the old plant also showed an 
inclination to become double. 
“This, at that time, to us, enigmatical phenomenon, was kept in mind 
until we had an opportunity of instituting comparisons between the 
climate of Japan and China and our own, and we then concluded that 
in the case of a plant imported from thence, and exposed to such 
different climatical influences, the origin of the greater or less imper- 
fection of its sexual organs was probably owing to this change, as we 
had experienced in Kerria and Camellia ; and that the sterility of many 
other exotic plants might be attributed to the same cause. The difference 
in the climatical relations of Japan and Europe is very considerable. 
In Japan, previous to the new growth of Kerria and Camellia, a rainy 
season of three months’ duration prevails; in Europe, on the contrary, 
dry winds prevail especially in the eastern part, where our plains are 
