.XX INTRODUCTION. 



superseded, it is still eminently useful as an index, or a 

 catalogue of the contents of its successor ; the secondary 

 use being one which, perhaps, Linnaeus himself scarcely 

 contemplated. 



It is not necessary here to give an account of the 

 various Natural Systems which have been proposed. 

 Suffice it to say, the one generally adopted in Britain 

 is a modification of those of Jussieu and De Candolle. 

 Here the whole Vegetable Kingdom is divided into three 

 great CLASSES. 



CLASS I DICOTYLEDOKES. 



In this Class are placed such plants as produce seeds 

 divisible into two lobes or cotyledons (p. 1). It is sub- 

 divided into Four Sub-classes, THALAMIFLOR^E, CALYCI- 



FLOR^E, COROLLIFLOR^E, and MoNOCHLAMYDE^E. 



Sub-class I. THALAMIFLOR^E. 



Flowers furnished with calyx and corolla ; petals 

 distinct, inserted into the receptacle, or thalamus \ 

 stamens springing from the base of the ovary. This 

 Sub-class contains Twenty-two British Orders. (Pp. 

 2133.) 



Sub-class II. CALYCIFLOR.E. 



Floivers furnished with calyx and corolla ; sepals dis- 

 tinct, or united ; petals distinct ; stamens inserted in 

 the calyx, or close to its base. This Sub-class contains 

 Eighteen British Orders, numbered from XXIII. to 

 XL. (Pp. 133292.) 



Sul-daSS III. COROLLIFLOR2E. 



Flowers furnished with calyx and corolla ; petals 

 united, bearing the stamens. In this Sub-class there 

 are Twenty-seven British Orders, numbered from XLL 

 to LXVIL (Pp. 292528.) 



