OF THE 



NORTHERN SECTIONS OF THE U. STATES, 



PARTICULARLY OP 



FIRST GRAND DimtSION, 

 PH.ENOGAMIA OR FLOWERING PLANTS. 



Plants consisting of a regular axis of growth with leafij appendages ; 



composed of a cellular^ vascular and ligneous structure ; 



developing flowers and producing 



seeds. 



SUBDIVISJON FIRST, 



EXOGENS OR DICOTYLEDONOUS PLANTS. 



Stem composed of distinct bark and pith with an intervening layer 

 of woody fibre and vessels. Growth by annual, concentric, 

 ■exteinal zones or layers. Leaves mostly with reticulated veins 

 and falling off by an articulation. Sepals and petals in 5s and 

 4s much oftener than in 3s. Embryo with 2 opposite, or several 

 whorled cotyledons. 



CLASS I. ANGIOSPERMS. 



Ovules produced within an ovary and fertilized by the pollen 



through the medium of the pistil, becoming seeds enclosed in 



a PERICARP. Embryo with two opposite cotyledons. 



SUBCLASS I. POLYPETALJ5. 



Floral envelops usually consisting of both calyx and corolla, the 

 latter composed of distinct petals. 

 B 



