OF BUDS. 107 



I cannot but assent to INIr. Knight's opinion, that each 

 individual thus propagated has only a determinate ex- 

 istence, in some cases longer, in others shorter ; from 

 which cause many valuable varieties of apples and 

 pears, known in former times, are now worn out, and 

 others are dwindling away before our eyes. New 

 varieties of Cape Geraniums, raised from seed in our 

 greenhouses, are of still shorter duration, and can be 

 preserved by cuttings for a few successive seasons only ; 

 yet several of these stand in our botanic uorks, with 

 all the importance of real species. Gardeners know 

 how many of the most hardy perennial herbs require 

 to be frequently renewed from seed to exist in full 

 vigour; and though others appear, to our confined 

 experience, unlimited in that respect, we have many 

 reasons to believe they are not so. Propagation by 

 seeds is therefore the only true reproduction of plants, 

 by which each species remains distinct, and all varia- 

 'tions are effaced ; for though new varieties may arise 

 among a great number of seedling plants, it does not 

 appear that such varieties owe their peculiarities to 

 any that may have existed in the parent plants. How 

 propagation by seed is accomplished will be explained 

 in a future chapter, as well as the causes of some va- 

 rieties produced by that means. 



Mr. Knight in the Philosophical Transactions for 

 1805, has shown that buds originate from the albur- 

 num, as might indeed be expected. The trunks and 

 branches of trees, and the knobs of genuine tuberous 



