the oldest in the world's history. Each of the classes is subdivided into two or more orders. Such is an outline of the system of classification of Linnæus. The system brings together, for no other purpose than for convenience of reference, plants dissimilar in structure, habit, and properties. It is an "artificial system," such as Linnæus always intended it to be. It has been superseded by the "natural system" of De Candolle, which is based on various natural systems. Linnæus knew the value of a natural system of classification. He says: "Methodi naturalis fragmenta inquirenda sunt. Primum et ultimum hoc in botanicis desideratum est. Plantæ omnes utrimque affinitatem monstrant uti territorium in mappâ geographicâ. … Methodus naturalis est ultimus finis botanicis. … Naturalis character ab omni botanico teneatur oportet." He left a slight sketch of a natural system; but the limited knowledge of genera and species in his day would have rendered such a system of classification imperfect and useless. Not so, however, "his artificial system, which, still marked by the limits that he assigned, not only offers facilities for forming an acquaintance with the names of plants, but affords ready means of reference to any system in which plants are arranged according to their natural characters." Although superseded, the system of Linnæus is still useful as an index; and even the present natural system "cannot be regarded as being perfectly evolved." Linnæus established the binomial
Page:Biographies of Scientific Men.djvu/98
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BIOGRAPHIES OF SCIENTIFIC MEN