GENUS : PLANT-NAMES 321 



Individual and species: variety and race.— When a red 

 clover seed is sown and allowed to grow it produces a single 

 plant, which after a time gives rise to a number of seeds, each ol 

 which can grow and produce offspring similarly, so that in a 

 few years a very large number of individual red clover plants 

 may be obtained. It will be found that these individuals, 

 although not exactly like each other, are nevertheless very 

 similar in the form, colour, size and other features of their roots, 

 stems, leaves and flowers. Such plants, and all those upon the 

 face of the earth which resemble them to such an extent that 

 they may be considered to have descended from a common 

 ancestor, are grouped together by botanists, the whole group 

 being termed a species. 



While the majority of the characters possessed by the various 

 organs of a species are constant, certain features, such as the 

 hairiness of the leaves and stems, or the colour of their flowers, 

 may vary : thus we may find in a field of red clover, plants 

 bearing white flowers instead of purple ones : such are described 

 as varieties of the red clover species. The peculiar characters 

 of a variety are usually transmitted to few or none of its 

 descendants. 



Varieties presenting some considerable variation from the 

 most prevalent characters of the species are termed sub-species or 

 races when the variation is known to be hereditary for many 

 generations. 



Many of our cultivated crops are. permanent varieties, or races 

 developed by the process of selection (see chap, xxiii.) from wild 

 species. 



Genus : plant - names. — Even cursory examination of the 

 various species of plants commonly met with, reveals the fact 

 that a certain number of them resemble each other, especially 

 in the form, arrangement and number of the parts of the flower. 

 Thus, red clover, Alsike clover and white clover, although differ- 

 ing from each other in the colour of their flowers and in the 



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