xlviii INTRODUCTION*. 



science might, be readily ascertained. With this in view, Rivinus invented, 

 in 1690, a system depending upon the conformation of the corolla ; 

 Kamel, in 1093, upon the fruit alone ; Magnol, in 1720, on the calyx 

 and corolla ; and finally, Linnaeus, in 1731, on variations in the sexual 

 organs. The method of the last author has enjoyed a degree of celebrity 

 which has rarely fallen to the lot of human contrivances, chiefly on account 

 of its clearness and simplicity; and in its day it undoubtedly effected its 

 full proportion of good. Its author, however, probably intended it as a 

 mere substitute for the Natural System, for which he found the world in 

 his day unprepared, to be relinquished as soon as the principles of the latter 

 could be settled, as seems obvious from his writings, in which he calls the 

 Natural System primum et ultimum in botanicis desideratum. He 

 could scarcely have expected that his artificial method should exist when 

 the science had made sufficient progress to enable botanists to revert to 

 the principles of natural arrangement, the temporary abandonment of 

 which had been solely caused by the difficulty of defining its groups. 

 This difficulty no longer exists ; means of defining natural assemblages, 

 as certain as those employed for limiting artificial divisions, have been 

 discovered by modern botanists ; and the time has arrived when the in- 

 genious expedients of Linnaeus, which could only be justified by the state 

 of Botany when he first entered upon his career, must be finally relin- 

 quished. We now know something of the phenomena of vegetable life ; 

 by modern improvements in optics, our microscopes are capable of revealing 

 to us the structure of the minutest organs, and the nature of their combi- 

 nation ; repeated observations have explained the laws under which the 

 external forms of plants are modified ; and it is upon these considerations 

 that the natural system depends. What, then, should now hinder us 

 from using the powers we possess, and bringing the science to that state 

 in which only it can really be useful or interesting to mankind 1 



Its uncertainty and difficulty deter us, say those who, acknowledging 

 the manifest advantages of the Natural System, nevertheless continue to 

 make use of the artificial method of Linnaeus. I do not know of any 

 other objections than these, which I hope to set aside by the following 

 remarks. 



First, as to its uncertainty. That it is not open to this charge, no one 

 will, I think, assert ; on the contrary, it is admitted on all hands that it 

 fully participates in those imperfections to which human contrivances are 

 subject, particularly such as, like natural history, are from their nature not 

 susceptible of mathematical accuracy. But while no claim is advanced 

 on its behalf to superiority in this respect over artificial methods, it may 

 be safely stated, that it is not more uncertain than the celebrated sexual 

 system of Linnaeus, the only one with which it is worth comparing 

 it. By uncertain, I mean that the characters of the classes and 

 orders of the Natural system arc not more subject to exceptions than 

 those of the Linnean, as perhaps may be proved from documents in 

 the hands of every English reader. We are so accustomed to believe that 

 the certainty of the sexual system is equal to its simplicity, that this opinion 

 has acquired the nature of a fixed prejudice, and Ave are perhaps not pre- 

 pared to assent to the truth of a contrary proposition. Without, however, 

 travelling out of the way, or seeking for proofs of it among books or plants 

 with whichthe reader is unacquainted, the following tableof exceptions to tbe 

 sexual system, taken from Smith's Compendium of the Flora Britannica, 

 may possibly carry some weight with it : 



