distinct reference to Cesalpino. He says that he establishes no classes himself, but only orders; if these are once obtained, it will be easy to discover the classes. The essence of the natural system could not have been more clearly expounded in Linnaeus’ time, than it is in these sentences. He established as early as 1738 sixty-five natural orders, which he at first simply numbered; but in the first edition of the ‘Philosophia Botanica’ in 1751, where the list is increased to sixty-seven, he gave a special name to each group; and he showed his judgment by either taking his names from really characteristic marks, or what was still better, by selecting a genus and so modifying its name as to make it serve as a general term for a whole group. Many of these designations are still in use, though the extent and content of the groups have been greatly changed. This mode of naming is an important point, because it expresses the idea, that the different genera of such a group are to some extent regarded as forms derived from the one selected to supply the name. Many of Linnaeus’ orders do in fact indicate cycles of natural affinity, though single genera are not unfrequently found to occupy a false position; at all events, Linnaeus’ fragment is much the most natural system proposed up to 1738, or even to 1751. It is distinguished from Kaspar Bauhin’s enumeration in this, that its groups do not run into one another, but are defined by strict boundaries and fixed by names. The Linnaean list is distinctly marked by the endeavour to make first the Monocotyledons, then the Dicotyledons, and finally the Cryptogams follow one another; that the old division into trees and herbs already rejected by Jung and Bachmann, but still maintained by Tournefort and Ray, disappears in Linnaeus’ natural system will be taken for granted after what has been already said of it, and from this time forward this ancient mistake is banished for ever.