SYSTEMATIC BOTANY 85 



where the species are all described and where keys 

 are provided so that any unknown plant can be identified 

 and named. 



With nearly a quarter of a million described forms to 

 deal with the value of such keys will be recognised. Let 

 us take an imaginary instance to illustrate the course 

 of procedure with a new species. Let us imagine that 

 in the English woods a plant very like a violet is found, 

 but that, instead of the plain purple petal of the ordinary 

 woodland species, it has a white fringed edge with red 

 spots on its veins. Its flower would therefore resemble 

 in some degree an orchid, and the finder would at once 

 examine it to see whether it is a new violet or an orchid. 

 We will imagine its leaves, however, to be similar to 

 those of the ordinary violet except for a red streak 

 down the main nerves. They would thus have net- 

 work veins, which would at once separate the plant 

 from the Monocotyledonous orchids. This, too, would 

 be indicated by the five petals and the structure of the 

 ovary. Let us imagine that the flower differs in no 

 particular from the ordinary violet except in the points 

 mentioned. Reference to an English flora would soon 

 show that it is at any rate a new species for this country, 

 but it may have been an " escape " from some garden 

 to which it has been brought from some foreign country. 

 The next thing to do is to look at the leading continental 

 and American and other floras in the family of Violaceae 

 for the different parts of the world. These can all be 

 seen at the British Museum. If such a plant is not 

 described in any of them, it still does not prove that 

 it is an unknown and therefore a new species. New 

 plants are described in such numbers that they are 

 not all incorporated in the current floras, and it might 

 well be that it had been published in the transactions 



