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90 NOTICES OF BOOKS. 
ten generations, both sets of plants left uncovered 
and naturally fertilised, produced capsules by weight 
as_ 100 to 51 
cold and of change in external conditions. Independently of any 
external cause, too, the self-fertilised are the more liable to premature 
eath. Moreover, asthe number of self- fertilised generations increases, 
there is often observed a coincident tendency to a decrease in the size 
of the anthers and in the production of pollen, and the flowers, besides 
becoming uniformly coloured, sometimes show signs of monstrosity, 
i 
occurred in 44 cases out of 58, and was shown very strikingly by a 
ss-flowered Cyclamen flowering some weeks before its self-fertilised 
species. 
~~ Mr. Darwin thinks that the assumption of hermaphroditism, due to 
a process of budding, may perhaps be explained by the risk which 
dicecious plants ran of not being fertilised. The relations between 
Dichogamy), and they would possess the advantage of sometimes 
ducing self-fertilised i 
capable of producing some self-fertilised seeds, while they are also 
capable of cross-fertilisation usually either by the aid of insects or of 
the wind; when, however, the structure of the flowers is such as to 
preclude self-fertilisation, they are in the same position one to another 
e 
