8TRUGTVBAL BOTANY. 5 



orders of flowering plants, which comprehend 800 genera ; 

 and these genera are represented by 2350 species. 



16. The classified plants have been designated by ap- 

 propriate names and distinguished by concise descriptions 

 in scientific language. 



17. But this language can not be understood before 

 one is somewhat acquainted with 8tnictural or Physiolo- 

 gical Botany. 



D. VEGETABLE LIFE IN GENEEAL. 



• 18. Physiological Botany is a science which treats of 

 the structure of plants, or of the organs, which enable 

 them to live and reproduce themselves. The successive 

 phases of vegetable life are Geemination, Growth, and 

 Kepeoduction. 



19. Plants are organized or living beings, possessing 

 the following attributes : 1st. The powee of self-support 

 OK assimilation — namely, the capacity to nourish them- 

 selves, by taking in surrounding mineral matter and con- 

 verting it into their own substance ; 2d. The power of 

 SELF-DIVISION OB EEPRODucTioN, by which they multiply 

 themselves and perpetuate the species. 



Plants alone a/re fitted to convert mineral into organic 

 matter, while a/nimals subsist solely on the organic matter, 

 elaborated in vegetables. 



30. There are only three chemical elements, which en- 

 ter into the permanent structure of plants — Carbon, Ey- ' 

 drogen, and Oxygen, while the tissues of an animal contain 

 an additional element— namely, Nitrogen. 



