50 EXPOSITION OF THE LINN/EAN' 



(already used by Jussieu and some other writers), 

 which might contain all genera with separated Flow- 

 ers, whose accessory organs differ in any respect. 

 This alteration has been adopted by an able practi- 

 cal botanist, whose experience taught him to approve 

 it, Mr. Frederick Pursh, in his Flora America Sep- 

 tentrionalis, published in 1814. He has divided the 

 Class Diclinia into the three following Orders. 



1. Segregate. Flowers not Amentaceous (53:3). 



2. Amentace.e. Barren Flowers, at least, in Cat- 

 kins (53:3); the Fertile ones not always so. 

 Fruit distinct from the Calyx, fig. 80, 87. 



3. Conifers. Barren and Fertile Flowers in Cat- 

 kins. Fruit a Strobilus or Cone, (61:7) fig. 276. 



Under each Order of the Linnsean System, are dis- 

 posed the Genera which belong to it, in a regular se- 

 ries, as nearly as possible according to their natural 

 affinity to each other, with the Essential Character 

 (104) of each. The Species are, in like manner, 

 ranged, according to their affinities, under each Ge- 

 nus, with their Specific Characters. Synonyms are 

 subjoined, with mention of the native country of each 

 Species; after which follow occasionally compen- 

 dious descriptions, with any useful remarks. Some 

 large Genera are commodiously divided into Natu- 

 ral Sections, by leading characteristics of certain 

 Species taken collectively. 



At the head of every Class, all its Orders are enu- 

 merated ; and under each Order its appropriate Ge- 



