AMERICAN 



WEEDS AND USEFUL PLANTS. 



SERIES I. 

 FLOWERING PLANTS. 



Plants v^ithjlou-ers, having stamens and pistils, and producing seeds, 

 which contain an embryo. 



CLASS I 



EXOG'ENOUS, OR DICOTYLE'DONOUS PLANTS. 



Stems distinctly formed of bark, wood and pith ; the wood, in stems 

 lasting from year to year, increasing by annual layers on the outside 

 next the bark. Leaves netted-veined. Embryo with two opposite 

 cotyledons, or rarely several in a whorl. Parts of the flower usually in 

 fives or fours. 



SUB-CLASS I. 



ANGIOSPER'MOUS EX'OGENS. 



Pistil a closed ovary, containing ovules and becoming the fruit. 

 Cotyledons 2. 



DIVISION 1. 



POLYPET'ALOUS EX'OGENS. 



Floral Envelopes consisting generally of both calyx and corolla^ 

 with the petals mostly distinct.^ 



* In the Rannnculacese sometimes the petals are absent, and in Leguminosse and 

 Cucurbitaceae, some species have the petals more or less united. 



2 . (25) 



