xxviii 



INTRODUCTION. 



ture of their flowers and seeds, but yet difler 

 so far, that they cannot be reduced under the 

 same genus; they are therefore placed with it 

 in the same natural order called Violace^, or 

 Violet Tribe, all the genera in which difler in 

 essential points from the genera which compose 

 other orders, but agree with a vast number in 

 having two-lobed seeds and leaves luith netted 

 veins, two of the characters of Exogens, The 

 flower of which we have been speaking belongs, 

 then, to the class Exogens, natural order Vio- 

 lace^, genus Viola, species odorata, of v/hich 

 species it is a white, or blue, or double variety. 

 In the Limiaean system, the same plant is placed 

 in the class Pentandria, which comprises flowers 

 having five stamens ; and in the order Monogynia, 

 which includes such of them as have but one 

 pistil. 



Every natural arrangement of plants professes 

 to bring together those which most resemble 

 each other in all respects ; and the reader will 

 see, from the following table, how far the pro- 

 mise is fulfilled with regard to those orders 

 which contain British trees. The botanical cha- 

 racters of each order are not given, partly to \ 

 avoid extending the introduction to too great ' 

 a length, and partly from the difliculty w^hich 

 attends the execution of such a task, without ^ 

 employing technical terms, which w^ould be un- 

 intelligible to the general reader. 



