210 



DOMESTIC BOTANY. 



CLASS VI.— EXOGENS. 



Embryo with two cotyledons. Leaves with netted 

 veins. Stems undefined or rudimentary only, or defined 

 and increasing in height and girth by the annual growth 

 of neio ivood to the exterior side of the preceding, en- 

 closed in true bark {fig. IS, a, b, c). 



Fig. 14. 



a. Seed germinating ; b. Vertical and transverse section 

 of stem ; c. leaf showing the netted veins. 



This class contains the greatest portion of the Vege- 

 table Kingdom, and is readily known by the leaves 

 being net-veined. It comprehends all the trees and 

 shrubs seen in the open air in this country, as well as 

 many herbaceous plants. The principal divisional cha- 

 racters of this class are derived from the flowers being 

 complete or incomplete, the corolla monopetalous or 

 polypetalous, and ovary inferior or superior, the primary 

 divisions being — 



1. Achlamyds. — Flowers generally unisexual, desti- 

 tute of calyx and corolla ; their absence being repre- 



