IM RODUI II- 



The true principles of classification, however much the) maj 

 amplified and refined upon, were in reality expressed b) R u be 



defin tural System to be thai which neither brings together d 



eparat which an nearly allied. However much the 



words of this definition may have been varied, it -till n 

 meaning given to it by it- author. .1 / aid Jussieu, 



individuals very much alike in all tht ir part . and r< taining their r< 



from generation to generation. '/'/<■■.■■ , 

 which corr n the g number of their chara 



■■•at is of more importance than mt chat On 



these two axioms hangs the whole principle of Natural n. — 



(Genera Plantarum Prajf.) And then he proceeded to show bow a group 

 of species combined upon this principle form I . an 



Order, and of Orders a I lass; the same rules of combination being observed 

 throughout, with this difference only, that the larger the group the fewer 

 the characters by which it is limited [Qud generalior enim < ttat plantarum 

 ordinal > qucelibet, ed paucioribus utitur signis definientibu 



I'. it it is far more easj to lay down principles than to put them in execu- 

 tion. The definition of Raj is perfect, but its application is surrounded 

 witli difficulty. The verj first point to settle in attempting to carry out his 

 views is by what rule the dissimilarity or alliance of specieB is to be di 

 mined. In fact, very different ideas of likeness or unlikeness are enter- 

 tained by different observers. The common people can Bee no difference of 

 moment between a Daphne, and a Cherry, ami a Rhododendron, but call 

 them all Laurels, although a Botanist fails to perceive their resemblance. 

 • Mi the other hand, there seems to the vulgar eye no connection bet\i 

 the Hemp plant and the Mulberry tree, and yet the Botanist brings them 

 into close alliance Nor are these conflicting views confined to the ignorant 

 and the uneducated ; Mich differences of opinion may he found among 

 Botanists themselves. For instance, Linnaeus joined Arum with Phyto- 

 lacca under hi- Piperita?, and Convolvulus with Viola under his Campa- 

 nacei, combinations which modern Botanists entirely repudiate ; and in 

 like manner th • association of Hugonia with Chlenads by Endlicher, of 

 Nepenthes with Birthworts by Brown, of Planes with Witch Hazels by 

 Adolphe Brongniart, of Vines with Berberries by the Author of this work, 

 el' Spurgeworts with Heathworts and < henopods by Pries, are so i 

 modern instances of peculiar views from which other Botanists withhold 

 their assent. 



It is therefore of tin 1 first importance t" Bettle with something like 

 precision what it is that con titutes likeness among plants, or. a- it is 

 technically called, their affinity. 



The reason why the vulgar commit mistakes in judging of nat 

 affinity is. because the) draw their conclusions from unimportant circum- 

 stances, the chief of which are size, form, and colour. The Bimilitud 

 size gave rise to the old notion that all tree- made a class h\ • 



which is a- if in a classification of animals the horse, the lion, and elephant 

 "ere placed in a different part of the animal kingdom from the rat. the 



ami the goat. Form i> another of the false guides which l< : if 



all round-leaved or square-stemmed plants are to be associal 



i;las.s to be (dassed with the diamond when it is cut to the -ame -haj.e. 

 Colour is le-s a BOUTCe of mi-take, and vet ir i- sometimes unco: 

 employed by the superficial observer, a- when lie calls ail yellow-flow 

 Composites Marigolds, ami all white-flowered vernal bushes Thorns. It 



