52 BOTANY. 



G, the white Birch, Juniper, &.c. ; and above all. at G, there occurs Genista 

 versicolor. Fig. 5 represents the distribution of American plants. Thus the 

 palm is found up to A ; arborescent ferns to B ; the grape to C ; cinnamon 

 to D ; oaks and the Mexican alder to E ; Pinus occidentalis to F ; maize to 

 G (probable snow line of Aconcagua) ; barley to H, On the eastern side, 

 Pinus occidentalis at F, and the Mexican alder and oaks at G. Fig. 6 

 illustrates the temperate zone of Europe ; the grape, chestnut and walnut, up 

 to A ; to B, oaks, white birch, red birch ; to C, Pinus picea and abies ; to D, 

 Alnus viridis and Rhododendron ; to E, Salix herbacea ; F to G, Pinus rubra ; 

 to H, oaks ; and the chestnut, the grape, &c., down to the foot again. Fig. 7 

 refers to the Canary Islands : to A, Palms ; to B, Cerealia and the grape ; 

 to C, Laurel trees ; to D, Pinus canariensis ; to E, Spartium rubiginosum ; 

 and to F, a species of Viola. Fig. 8 shows the distribution of plants in the 

 frigid zone of Europe ; Pinus sylvestris to A ; the white birch to B ; and to 

 C, Salix herbacea and lanata. 



SYSTEMATIC BOTANY, OR THE CLASSIFICATION OF 



PLANTS. 



It does not come Avithin the scope of the present work to give a history 

 of the rise and progress of the science of Botany, nor to enumerate the 

 various systems of classification which have been propounded. We will 

 merely state that such systems are either artificial or natural. The most 

 important artificial system is that of Linnaeus, which, better perhaps than 

 any other system affords an index to the genera. The objection to this 

 and to other artificial systems is, that genera and species of very different 

 character are necessarily brought together, while their affinities and truly 

 essential characters may be wholly opposite. Up to a comparatively recent 

 period the system of Linnaeus almost exclusively prevailed ; few botanists of 

 the present day, however, make any other use of it than that of a key or index. 

 In this system twenty-three classes are founded on the number, relative 

 lengths, position, and connexion of the stamens ; the orders in these classes 

 depending on the number of styles, the nature of the fruit, occasionally the 

 number of stamens, and the perfection of the flowers. The twenty-fourth 

 class includes plants with inconspicuous flowers. The following is a tabular 

 view of the system as analysed by Balfour. 



Tabular View of the Classes of the Linncean System. 



A. Phanerogamia (Flowers present) : 

 I. Stamens and Pistil in every flower. 

 1. Stamens free. 

 a. Stamens of equal length, or not differing in certain proportions : 

 Class 



52 



