11 1902 



THE PROGRESS MADE IN BOTANY DURING THE 

 NINETEENTH CENTURY.* 



William Trelease. 



what botany stood for at the beginning oe the century. 

 At the beginning of the Nineteenth Century about 25,000 

 species of plants had been described, and, though consider- 

 able use had long been made of other species which at the 

 beginning of the century were unclassified and unnamed by 

 botanists, the number of these were relatively small, so that 

 the entire knowledge of botany, economic as well as scientific, 

 and in all of its branches, was practically confined to the 

 limited number of species mentioned. This knowledge con- 

 sisted in a recognition of their specific differences and the 

 rather superficial affinities and relationship deduced from 

 these in a great but often hopelessly scattered and frequently 

 erroneous literature, and in popular acquaintance with their 

 useful properties — particularly their medicinal virtues, and a 

 general blocking out of their anatomy and physiology, — to 

 no small extent a matter of subjective opinion. 



SYSTEMATIC BOTANY. 



About the middle of the preceding century, Linnaeus had 

 elaborated a workable, if artificial, system of classification, 

 which, with brief but sharp diagnoses, made it reasonably easy 

 to ascertain whether a given species of plant in hand had been 

 previously described or was new to science; and as he had 

 combined with this the very simple expedient of referring to 

 the several species by latinized binomials instead of by de- 

 scriptive phrases, the naming and describing of species ha,s 

 proved not only one of the most necessary but also one of the 

 easiest and most popular branches of this as well as of the 

 related biologic science, zoology, during the century just 

 closed. 



* An address delivered before The Academy of Science of St. Louis, 

 November 8, 1901. 



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