THE CLASSIFICATION OF THE PLANTS. 155 



or it may be made up of a number of elementary species. Thus the 

 species of the botanist are by no means equal in value. In practice, 

 however, if a number of plants resemble one another almost exactly, 

 they may at once be concluded as belonging to the same species. 



If a number of species agree in certain particulars so that we may 

 conclude they have descended from some common ancestor, they are 

 said to belong to the same genus, and we have the next wider group 

 of plants. Suppose we find a number of plants which, although they 

 differ much in stature, shape of leaves, habit of growth, size and colour 

 of flowers, and in other particulars, yet have all four petals, eight 

 stamens, the calyx-tube attached to the ovary, and produce after 

 flowering a narrow, elongated, 4-angled capsule, which splits open 

 from the apex downwards into four sections, revealing a large number 

 of seeds, each provided with a tuft of hairs at the apex, then all those 

 plants will belong to the genus Epilobium (fig. 63). These plants, again, 

 will vary much amongst themselves ; but groups having distinguishing 

 marks for each group can be found, and such groups will each repre- 

 sent a species. There are in New Zealand between thirty and forty 

 species of Epilobium, which are distinguished from one another by 

 distinctive marks, and each bears a name e.g., Epilobium glabellum, 

 E. Hector i, E. y,ubens, &c. 



Originally the second name had a meaning which was supposed 

 to be appropriate to the plant, but the number of specific names has 

 so increased during the past hundred years that it is no longer possible 

 always to find an appropriate appellation. So modern botany has 

 decreed that a specific name once given must stand for ever, even 

 where the name is quite inappropriate. This means that a name is 

 now considered merely as a name and nothing more, and need have no 

 meaning whatsoever. 



Another matter which must be remembered is that generic differ- 

 ences generally depend on the structure of the flowers, and not on the 

 leaves. That a plant has leaves like a willow does not constitute it 

 a willow ; similar plant-form, as has been already shown in this 

 book, occurs amongst plants quite unrelated. Leaves, however, 

 amongst other characters, are made use of as marks of specific 

 differences. 



Finally, before leaving this matter of names, it must be pointed 

 out that the naming of plants is merely a preliminary, though neces- 

 sary, study of the flora of a country. A man might easily know the 



