LIJTNJEAN SYSTEM. 249 



distinguished from the preceding by its having a pair 

 of very distinct double celled anthers, and by its large 

 inflated nectary. In the order Hexandria we find 

 Aristolochia ; and the Virginia Snake root, well known 

 throughout the country will serve as an example. 

 Other species of this singular genus occur in the 

 Southern states. 



Monoecia.-Several late writers have abolished this and 

 the two following classes, and when the structure of the 

 accessory parts of the flower is the same, Dr. Smith is 

 inclined to admit the change as an improvement. " But 

 with respect to those Monoecious or Dioecious genera 

 whose barren flowers are decidedly unlike the fertile 

 ones, the former being in a catkin, and the latter not, 

 as in the Chesnut and Oak, I conceive nothing more 

 pernicious or troublesome can be attempted than to 

 remove them to the classes of united flowers. They 

 meet with no allies there, but, on the contrary, form 

 so natural an assemblage by themselves, as to be unan- 

 imously kept separate by the authors of every natural 

 system that has appeared."* 



In the first orders of this class we meet with a few 

 aquatic plants and a few Grasses. In the fourth we 

 find the Birch and Nettle, Amaranthus in the fifth. 

 Zizania or wild Rice in the sixth, and in the remaining 

 orders, the Oak and many other of the forest trees. 



The class Dioecia having eight orders is illustrated 

 by Valisneria, Me?iispermum ) Dioscorea, Persimmon 

 and Poplar. 



The class Polygamia, having different flowers on 

 the same, and on different plants, has been abolished 

 by many writers. Dr. Smith proposed to unite it with 



* Smith's Introduction. 



