DIRECTION OF VARIATION. 65 



4. Some plants in their native state give indications of the 

 kind of change likely to take place in them by cultivation. 

 The rose, for example, by its large corolla in comparison with 

 the fruit, shows that change of flower is most likely to take 

 place. In the apple, the large fleshy fruit indicates a tendency 

 to variation and improvement in that direction. The viburnam 

 opulus, the hydrangea, and other plants, by the circle of sterile 

 flowers, much larger and more beautiful than the fertile flowers, 

 indicate change in the direction of beauty. These beautiful 

 circles of sterile flowers in some of our native shrubs, and the 

 neutral rays of some of our composite, may be regarded as 

 ornaments, rather than as of use, in the economy of the plant. 

 When, therefore, a new plant is brought under cultivation, 

 there is little doubt in what direction it will vary, if at all. 



5. Those plants that by variation lose the power of producing 

 seed, can always be propagated in other ways, as by slips or 

 bulbs. Nature, as though careful for the preservation of the 

 species, never allows any plant, by its own law of growth, to lose 

 the power of producing seed, unless she has given to it means 

 other than the seed for the perpetuation of its kind. 



6. Variation is most common and rapid in those plants which 

 are most useful to man for cultivation, and which must go with 

 him over most of the earth. It may be said that they are most 

 useful because they happen to vary. But their readiness to 

 vary certainly was not the cause of their first cultivation. They 

 were selected for some particular good, as for fruit, or for beauty 

 of flower, or some other useful property. The characteristic 

 for which each one was first selected was the leading idea of the 

 plant, and in that direction all its variations under cultivation 

 have tended. The rose, in all its varieties, is to-day cultivated 

 for the same reason for which it was first cultivated — for its 

 beauty ; the apple-tree for its fruit ; the sugar-cane for its 

 sweetness ; and so on through the list of cultivated plants. 



We might multiply propositions and examples, if our space 

 allowed. As they would not differ in kind they are not needed 

 for the argument. Apparent exceptions to the propositions 

 already stated may undoubtedly be pointed out, for it is well 

 understood by naturalists that Nature does nothing per salt urn. 

 Hardly a group of plants can be examined in which there will 

 not be found one or more that the family description will not 

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