AMERICAN 



WEEDS AND USEFUL PLANTS. 



SERIES I. 

 FLOWERING PLANTS. 



PLANTS with flowers, 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 Ranunculacene sometimes the petals are absent, and in Legumincsse and 

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



2 (25) 



