THE CLASSIFICATION OF PLANTS. 395 



issued originally from one common stock. Thus if we walk 

 into a fiekl of Wheat, Barley, or Oats, we observe thousands of 

 individuals, which, although differing to a certain extent in size, 

 and in some other unimportant characters, we at once associate 

 together under a common name. In like manner we commonly 

 observe around us, in the gardens and fields, similar collections 

 of individuals. Such collections of plants, thus seen to resemble 

 each other in all their important parts, constitute our first idea of 

 a species ; and that idea is at once confinned if, by taking the 

 seeds of such plants and sowing them, we obtain other plants 

 resembling those from which such seeds have been obtained. 



Varieties. — It has just been observed, that if the seed of a 

 species be sown it will produce a plant resembling its parent 

 more than it will resemble any other individual. This will, 

 however, only happen, when the new individual has been exposed 

 to similar influences of soil, heat, light, moisture, &c., as its 

 parent ; and hence we find that any variations in these particulars 

 will lead to certain peculiarities in form, colour, size, and other 

 minor characters, in plants raised from the seeds of the same 

 species. In this manner we have formed what are termed 

 varieties. In some cases such variations are merely transient, 

 and the individuals presenting such peculiarities will in time 

 return to the original specific type, or perish altogether; while in 

 other instances they are permanent and continue throughout 

 the life of the individual, the whole plant being, as it were, im- 

 pregnated with the particular variations thus impressed upon 

 it, and hence such variations may be perpetuated by the gardener 

 in the operations of Budding, Grafting, &c. (see Budding, &c.), 

 as is the case Avith many of our fruit trees and flowers. Even 

 these varieties, however, cannot be propagated by seed, for if 

 their seeds be sown, the individuals which will be produced will 

 have a tendency to revert to the original species from which 

 such varieties have been obtained, so that the nature of the plant 

 raised will depend chiefly upon that of the soil, &c., in which it 

 is placed. Thus, if we sow the seeds of a number of different 

 kinds of Apples, the fruit which will be afterwards produced by 

 the new generation of Apple trees, will, instead of resembling 

 that of their parents, have a tendency to revert to that of the 

 Common Crab, from which species all such variations have been 

 originally derived. Hence a variety differs from a species in the 

 fact that it cannot be propagated by seed. 



Races. — Besides the varieties just alluded to there are 

 others, which are called permayient varieties or races, because 

 their pecuharities can be transmitted by seed. Famihar ex- 

 amples of such races are afforded by our Cereal grains, as 

 Wheat, Oats, Barley, &c., and also by our culinary vegetables, 

 as Peas, Lettuce, Eadishes, Cabbages, Cauliflower, Broccoh, 

 &c. Similar permanent varieties occur in the Animal Kingdom 



