INTEODUCTION. 



DURING the last century the means of acquiring knowl- 

 edge in every department of science has been wonder- 

 fully increased and facilitated. In the several departments of 

 Natural History the improvement has been striking. Natural- 

 ists no longer study any branch as a whole, but divide it into 

 parts, each of which affords employment for a lifetime. Thus, 

 in Zoology, one naturalist devotes himself to Quadrupeds, 

 another to Bu-ds, a thud to Fishes, and a fourth to Insects. 



It is less than a hundred years since Botany was allowed a 

 place as a branch of Natural History ; nevertheless it has not 

 only become a favorite study, but is now a very important 

 branch of science. The field has so enlarged itself that it has 

 been found convenient, as in other sciences, to break it up into 

 several departments. 



The number of species of plants was supposed by Linnaeus 

 not to exceed ten thousand, while at the present day about one 

 hundred and fifty thousand are known ; and new species, and 

 even new genera, are yearly increasing the names already in 

 the vast catalogue. 



The constant expansion of this broad field is a source of the 

 highest gratification to the student of Natural History. He 

 need entertain no fears that his insatiable curiosity will ever 

 lack food ; a long life given to the study of Botany in any one 

 of its departments, with the most zealous and enthusiastic 

 devotion, will leave it still unfinished. No branch of science 

 affords such unalloyed pleasure in its pvn'suit. 



He who sees no beauty in the expanding Rose or tiie Tulip's 

 variegated petals is, indeed, an object of pity. Even a common 



