112 MASSACHUSETTS HORTICULTURAL SOCIETY. 



Organology refers to the external structure of plants, vegetables 

 being reduced to two classes, as complicated or simple, or perfect 

 and imperfect. The organs of perfect plants are divided into 

 conservative, as the root, trunk, branch, and leaf; and the repro- 

 ductive, as the flower stalk, flower, receptacle, and fruit, all of 

 which, though temporary, are indispensably necessary to their 

 propagation. 



Vegetable Anatomy, or the internal structure of plants, is the 

 most interesting part of the study of the vegetable kingdom. The 

 internal organs are reducible into component ones, called decom- 

 posite, composite, and elementary. The first are those which by 

 the annual process of the sap are changed, in plants of a soft or 

 juicy nature, into composite organs, or solid or woody fibre. These 

 composite organs are of different substances, as the pith, the wood 

 or vegetable fibre, and the outer cuticle or integument. The 

 elementary or vascular organs are situated in the wood or between 

 the wood and integument, and are the vessels which conduct the 

 sap or proper juice to ever}^ part of the plant. 



Vegetable Chemistry relates to the different substances produced 

 by plants. All plants, whether trees, shrubs, or weeds are more 

 than merely organized beings, having the power of absorbing 

 nourishment from the earth, and by the operation of their organs 

 elaborating it into substances useful in the arts, or necessary for 

 the sustenance of the animal world, such as gums, resins, wax, 

 balsams, starch, sugar, oils, cork, camphor, charcoal, ashes, 

 alkalies, salts, extracts, tannin, caoutchouc, acids, etc. 



Vegetable Physiology involves the germination, nutriment, 

 digestion, growth, development of parts, propagation of the 

 species, causes limiting the dispersion of their seeds, the 

 evidence of the vitality of plants, etc. The last named point 

 was observed by Linnaeus, and published in his works. As with 

 animals, so with plants ; when the vital principle is extinct the 

 organs cease to act and decay commences. Among the proofs of 

 the vitality of plants are their sensibilit}'^ to the stimulating 

 influence of light and ' heat, and their instinct. Even in the 

 coldest winter, when all vegetation seems totally at a stand, and 

 the plant is stripped of every vestige of foliage, the vital princi- 

 ple is still at work, but as the warmth of spring returns the more 

 rapid circulation of their juices renders their effect visible. The 

 tendency of plants to incline tlieir stems and turn the upper 



