366 Ever-sporting Varieties 



the old roots. Double tuberous begonias are or- 

 dinarily absolutely sterile throughout the sum- 

 mer, but towards autumn the new flowers be- 

 come less and less altered, producing some nor- 

 mal stamens and pistils among the majority of 

 metamorphosed organs. From these flowers the 

 seeds are saved. Sometimes similar flowers 

 occur at the beginning of the flowering-period. 

 Double garden-camomiles {Chrysanthemum, in- 

 odorum plenissimum) and many other double 

 varieties of garden-plants among the great 

 family of the composites are very sensitive to 

 external agencies, and their flower-heads are 

 fuller the more favorable the external condi- 

 tions. Towards the autumn many of them pro- 

 duce fewer and fewer converted heads and often 

 only these are fertile and yield seeds. 



Ascidia afford another instance of this 

 periodicity, though ordinarilj^ they are by far 

 too rare to show any regularity in their distri- 

 bution. However, it is easy to observe that on 

 lime-trees they prefer the lower parts of each 

 twig, while on magnolias the terminal leaves 

 of the branches are often pitcher-bearing. 

 Ascidia of the white clover have been found 

 in numbers, in my own experiment-garden, 

 but always in the springtime. The thick- 

 leaved saxifrage {Saxifraga crassifolia) is 

 often very productive of ascidia, especially in 



