u 



HISTORY OF THE VEGETABLE KINGDOM. 



also a striking example of this tendency of the 

 latent huds of the root, to change into leafy 

 branches when placed in the air, in those shoots 

 which sprout up around trees, which have creep- 

 ing roots, such as the acacia and poplar. The 

 roots of certain trees, at different distances, pro- 

 duce a species of cones, or excrescences of a 

 loose, soft wood, quite naked, and standing ahove 

 ground, which are called exostoses. The cypress 

 of North America affords an example of this. 

 The root is commonly divided into three parts. 

 The body or middle part, of various forms and 

 consistences, sometimes more or less swelled, as 

 in the turnip and carrots. The coUar or life 

 knot, an annular hulge at the point where the 

 stem joins the root, and from which springs the 

 bud of the annual stem, in perennial roots. The 

 radical or minute branching fibres, which ter- 

 minate the root. Roots, according to their dur- 

 ation, are distinguished into biennial, perennial, 

 and woody. Annual roots belong to those plants 

 which, in the course of one year, come to their 

 maturity and perish, such as wheat, cockspur, 

 poppy, &c. Biennial roots are those of plants 

 which require two years to come to maturity. 

 During the first j'ear, biennial plants usually 

 produce nothing but leaves ; in the second year 

 they perish, after having flourished and produced 

 fruit, as the caiTot. The perennial roots are 

 those which belong to woody plants, and to those 

 which, during an indefinite number of years, 

 send forth herbaceous stems, which annually 

 flourish and decay, while the root lives for several 

 years, such as those of asparagus, asphodils, lu- 

 ccrn. This division of vegetables, however, into 

 annuals, biennials, and perennials, according to 

 the duration of tlieir roots, is liable to vary under 

 the influence of divers circumstances. The 

 climate, temperature, and situation of a country, 

 and even cultivation, influence, in a singular de- 

 gree, the duration of vegetables. It is no un- 

 common thing to see annual plants vegetate for 

 two years, and even more, if they are placed in 

 a suitable soil and protected from the cold. 

 Thus, the mignonette, whicli, in Europe, is 

 only an annual plant, becomes perennial in the 

 sandy deserts of Egypt. On the contrary, per- 

 ennial, and even woody plants of Africa and 

 America, become annuals when transplanted into 

 northern climates. The marvel of Peru and 

 oobcea, are perennial in Peru, and die annually 

 in our gardens. The castor oil plant, which in 

 Africa fonns woody trees, is annual in our climate, 

 yet it again resumes its woody character when 

 placed in a proper exposure. In general, aU 

 perennial exotic plants, wliose seeds can produce 

 individuals that flower the first year in our 

 climate, become annuals. This is the case with 

 the castor oil plant, the coboea, marvel of Peru, 

 &c. Woody roots differ from perennial only 

 in their more solid consistence, and in the per- 



manency of the stems which they support, such 

 as those of trees and shrubs. There are four 

 principal divisions of roots : 1st, Vertical, or 

 those which sink perpendicularly into the earth. 

 2d, Fibrous, or those branching out into fibres. 

 3d, Tuberous, having round or oval appendages. 

 4th, Bulbous, having a bulb at the top. 



1. Vertical roots are those which sink perpen- 

 dicularly into the earth, as the carrot, c, turnip, i, 

 14. 



and radish. They are either simple, as in tliis 

 vegetable ; or branched, as in the ash, a. They 

 belong exclusively to the class of Dicotyledonous 

 vegetables. They are not true roots, however, 

 but merely give off the fibrils, or proper roots. 

 2. The fibrous root d, consists 

 of a great niimber of fibres, which 

 are either simple and slender, 

 or thick and ramified. The roots 

 of a great proportion of the 

 palms are of this kind, and such 

 roots are found in the Monoco- 

 tyledonous class only, 

 d 



3. Tuberous roots are tliose which have at- 

 tached to the true root, at different points, some- 

 times at the upper part, sometimes in the middle 

 or at the extremities, tubers or roundish bodies. 

 '^- (fig. lG,e). These tubercles or 



fleshy bodies, which are com- 

 monly, though erroneously, 

 called roots, are only masses of 

 a starchy consistence and sub- 

 stance, wliicli nature has thus 

 stored up, to afford a supply 

 of nutritious matter for tlie 

 future germ. They are more 

 or less numerous, as in the 

 Jerusalem artichoke and potatoe. They are 

 never found in annual plants ; but belong ex- 

 clusively to perennial. Sprengel considers these 

 tubercles as a kind of subterranean buds, to 

 which nature has confided the preservation of 

 the rudiments of the stem. The only difference 

 which the tubercles, thus considered, present, is 

 that the young stem, in place of being -protected 

 by numerous and close scales, is enveloped by a 

 dense and fleshy body, which not only serves to 

 protect it during winter, but supplies it in spring 



