9 8 SECRETS OF EARTH AND SEA 



C-album. There are other European, Asiatic, and 

 American species of Vanessa. 



In the same way we find with our meadow plants that 

 what we at first thought was a single kind, " the " buttercup 

 really bears a name applicable to a genus in which are 

 several common species. The genus is called Ranunculus, 

 and there are several common English species with yellow 

 flowers, but distinguished from one another by definite 

 characters. They are Ranunculus acris, Ranunculus 

 flammula, Ranunculus bulbosus, Ranunculus arvensis, 

 Ranunculus ficaria (the lesser celandine). And then there 

 is the white-flowered Ranunculus aquatilis — a common 

 pond plant. Clover, again, is by no means the name for 

 a single species. The clovers form the genus Trifolium, 

 and in any English meadow we may come across the 

 white clover, Trifolium repens ; the red clover, Trifolium 

 pratense ; the hop clover, Trifolium agrarium : the straw- 

 berry clover, Trifolium fragiferum ; the haresfoot clover, 

 Trifolium arvense. So it is with the plants which at first 

 sight we distinguish merely as " daisies." There are 

 several distinct genera of daisies — Aster, Bellis, Chry- 

 santhemum (ox-eye), Anthemis (camomile), and others, 

 with several distinct species in each genus. 



Enough has been said to show the reader that the 

 mere notion of " kinds " does not carry the same meaning 

 as " species," but that there are a number of regularly 

 occurring definite forms of both animals and plants which 

 can be arranged in groups consisting only of individuals 

 which are very nearly identical with one another. A 

 group of living things of this degree of likeness is called 

 " a species," and receives a name. A less degree of like- 

 ness holds together a number of species to form what we 

 call a genus, and the name of the genus is cited together 

 with the name of the species when we wish to speak of the 

 species with clearness and certainty. This system of 



