Horticultural Chemistry. 131 



The subject of the present paper is the root of plants, its 

 offices, the mediums in which it grows, the nourishment it 

 obtains to its parent plant, &c. ; consequently, it includes the 

 consideration of soils, manures, &c. 



The root is present in all cultivated plants. The truffle, 

 which, however, can scarcely be considered as belonging to 

 cultivated vegetables, having hitherto defied all attempts to 

 subjugate it, may be considered as consisting of nothing but 

 root. A root is annual, biennial, or perennial. In the two 

 former instances, if the individuals to which they belong be 

 allowed to perfect their seed, no care can protract their ex- 

 istence beyond the ensuing winter, however genial the tem- 

 perature, &c, in which they are made to vegetate ; but, if the 

 ripening of seed be prevented, it is undetermined how long they 

 may in most instances be sustained in life. I have known 

 mignonette continued in healthy vegetation for four years 

 with this precaution. In all roots, and under any mode of 

 management, the fibrous parts (radiculae) are strictly annual; 

 they decay as winter approaches, and are produced with the 

 returning vigour of their parent in the spring. Hence the 

 reason that plants are transplanted with most success during 

 the season of their decay : for, as the root almost exclusively 

 imbibes nourishment by the mouths of these fibres, in propor- 

 tion as they are injured by the removal, so is the plant de- 

 prived of the means of support ; that sap which is employed 

 in the formation of new fibres, would have served to increase 

 the size of other parts. The size of the root I have always 

 observed to increase with the poverty of the soil in which it 

 is growing. Duhamel found the roots of some young oaks 

 in a poor soil to be nearly four feet long, though the stem 

 was not more than six inches. The cause of this is evident : 

 the nourishment which is required for the growth of the 

 plant, can only be obtained by an increased wide-extending 

 surface of root, and, to form this, more sap is often required 

 than the plant, owing to the poverty of the earth, can obtain to 

 itself; in that case a soil is sterile, for the plant must evidently 

 perish. Every one may have noticed this familiarly in- 

 stanced in P6a annua growing on a gravel walk, its stem 

 minute, its root a mass of widely extending fibres. A root 

 always proceeds in that direction where food is most abun- 

 dant ; from a knowledge of this fact, we should be circum- 

 spect in our mode of applying manures, according to the crop 

 and object we have in view. The soil in my own garden, 

 being shallow, never produced a carrot or parsnep of any size ; 

 but almost every root consisted of numerous forks thickly 



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