INTEODUCTOEY CHAPTEE. 



Plants are oi'g'anized living beings, void of feeling and voluntary motion ; they 

 constitute the Vegetable Kingdom; and Botany, which is the natural history of 

 the Veyetahh Kingdom, treats of plants, firstly, individually ; secondly, collectively ; 

 and thirdly, veith regard to their uses to man. The whole subject may be con- 

 sidered under three principal heads. 



The first includes Organography, which treats of the foruj and S3'mmetry of the 

 organs of plants ; Anatomy, of their interior structure ; Physiology, of their func- 

 tions; and Glossology, of the technical language employed to describe the organs and 

 their modifications. 



The second includes Taxonomy, the classing of plants according to their 

 affinities ; Phytography, the description of species ; and Nomenclature, the names 

 given to species by botanists. 



The third includes Agriculture, Horticulture, ArhoricuUure, Medical and Economic 

 Botany. 



1 1 (((( 



The tissues of a plant present to the naked eye two very distinct elements, 

 named j/Jfero-vascM^ar bundles and cellular tissue {parencliyma). The first consists of 

 tenacious fibres gathered into bundles, or spread out like network, and forming 

 the more solid portion of the plant; the second is a spongy, 

 succulent substance filling the spaces between the fibres, being 

 especially abundant in leaves and fleshy fruits, and constituting 

 the softer portion of the plant. When magnified, these tissues 

 present various structures, the components of which, called 

 elementary organs, will be described in a future chapter. 



An ordinary plant consists of a cylindric body (fig. 1), more 

 or less branched at its two extremities, and bearing laterally 

 leaves of various forms, which are either scattered or grouped. 

 The upper portion of this body, the stem {caulis, t), bears the 

 leaves (f, p), and is green (at least in the young shoots) ; it 

 branches from the ground upwards, diminishing in thickness as 

 it branches. The lower portion, the root {radios, e), is leafless 

 and subterranean, of a pale colour, and branches from above 

 downwards, diminishing in thickness the deeper it penetrates the earth. 



Thus the stem and root are ^nited where their girth is greatest, and are deve- 

 loped in opposite directions ; the former always tends to ascend, and the lower to 



1, Stock. Boot and lower 

 portion of stem. 



