OF SEED-SAVING. 173 



the young fruit alone is generated. In all cases of 

 this kind, the remedy for sterility is obvious enough 

 where plants exist in an artificial. condition ; but, when 

 they occur in the orchard or the flower-garden, in the 

 open air, science suggests no assistance. 



It sometimes happens that particular parts of plants, 

 distant from the fruit, are so constructed as to attract 

 to themselves the food intended for the fruit, and thus 

 to prevent the formation of seed. For example : — 

 The early varieties of Potato do not readily produce 

 seed, owing to the abstraction by their tubers of the 

 nutritive matter required for the support of the seed. 

 Mr. Knight found that by destroying the tubers in 

 part, as they formed, seeds were readily procured from 

 such varieties.* 



But perhaps the most frequent cause of sterility 

 is the monstrous condition of the flowers of many cul- 

 tivated plants. It has been fully explained (84) that 

 the floral organs of plants are nothing more than 

 leaves, so modified as to be capable of performing 

 special acts, for particular purposes ; but they are 

 not capable of performing those acts any longer than 

 they retain their modified condition; and therefore 

 the stamens cannot secrete pollen, when, by acciden- 

 tal circumstances, they are changed into leaves, as 

 happens in double flowers; then, there is nothing 



* Viae versa, the produce of the potatoes may be much increased 

 by plucking off the blossoms, in ■which case the nutritive matter 

 which would have been expended upon them and the berries, or 

 fruit, serves to increase the size of the tubers, for which alone the 

 plant is cultivated. This fact, so perfectly consistent with theory, 

 has been completely confirmed by experiment. 



