INTRODUCTION TO BRITISH BOTANY xv 



directly from the roots. The Dog- Violet is therefore a distinct 

 species, Viola canina. The Marsh- Violet and Pansy differ also in 

 important characters ; they are, therefore, also considered distinct 

 species, the fact being indicated by the addition of the specific or 

 trivial names, palustris and tricolor, to the generic name Viola. The 

 flowers of the scented Violet are sometimes white and sometimes 

 i )lue ; garden specimens are often tinged with pink, and still more 

 frequently, double. These characters being either unimportant or 

 inconstant for blue flowers generally have a great tendency to 

 sport to white, and double flowers are not perpetuated by seed 

 the blue, white, pink, and double sweet Violets are not considered 

 distinct species, but mere varieties. Now there are many plants 

 which bear a close resemblance to a Violet in the structure of their 

 flowers and seeds, but yet differ so far that they cannot be reduced 

 under the same genus ; they are therefore placed with it in the 

 same Tribe, called Violace.e, all the genera in which, differ in essen- 

 tial points from the genera which compose other Tribes, but agree 

 with a vast number in having two-lobed seeds and leaves with netted 

 veins, two of the characters of Dicotyledonous Plants. In this 

 Class it is arranged with plants furnished with both calyx and 

 corolla, and having their petals distinct and inserted with the 

 stamens into the receptacle. 



The plant of which we have been speaking belongs, then, to the 



Class I. DICOTYLEDONS. 



Sub- Class I. Thalamiflor.e. 



Order or Tribe IX. Violace.e. 



Genus I, Viola. 



Species 2, odorata. 



Variety, blue, white, or double. 



B 



