%4A EXPLANATION OF THE 



Triandria has three orders ; Iris, Ixia and Crocus oc- 

 cur in the first, as well as the Cyperoidece ; most of 

 the Grasses occur in the second ; and Holosteum and 

 Carpet-weed will exemplify the third. 



Tetrandria has four orders ; Houstonia, Mitchella, 

 Lin/uBd, and Frasera occur in the first, all dedicated 

 to the memory of worthy botanists, two of whom re- 

 sided in this country. Galium and Scabious will 

 also serve to illustrate this order. The second and 

 third orders are extremely rare, and in the fourth 

 we meet with but few plants of interest. The Holly 

 is one. 



Pentandria has seven orders. The first, (Monogynia,) 

 is probably the most extensive in the system of Lin- 

 naeus ; embracing more than sixty genera within the 

 limits of the United States. Among these are the 

 Lurid and the Rough-leaved plants, the former ex- 

 emplified in Stramonium, and the latter in Borage. 

 Azalea, Phlox, Convolvulus and Ipomoza are among 

 the most interesting Genera which fall within the 

 limits of this extensive order. In the second, we 

 find the umbellate plants ; in the the third, the Elder 

 and Viburnum; in the fourth, Parnassia ; in the fifth. 

 Aralia, Marsh Rosemary and Flax ; and in the sixth, 

 we have Zanthorhiza, or Yellow Root. 



llexandria has six orders. The first includes the 

 Lilies ; the second has Oryza, or Rice ; the third 

 has Trillium and Gyromia ; the fourth has Saururus ; 

 the fifth has Wendlandia ; and the sixth (Polyginia) 

 has Alisma, or Water Plantain. 



Heptandria embraces but two genera within the limits 

 of the United States, the Horse Chesnut and Trienta- 

 lis, both of the first order. Africa furnishes a single 

 genus with two, and another with seven pistils. The 



