129 



aggregately tjualified to perform the same functions in nour- 

 ishing the plant. 



Further : Roots are materially determined in their form 

 by the nature of the soil in which they grow ; insomuch that, 

 in many instances, before we can pronounce on their true 

 form, we must be aware of the condition and texture of the 

 soil that is most natural. to them. Their development is 

 most luxuriant in ground that is neither too loose nor too 

 dense. In stiff and poor soils, they are spare and scraggy ; 

 whereas, in such as are at once deep and loose, the minutest 

 fibres-both expand and elongate with facility, and render the 

 mouths, that search for food to the plant, almost innumera- 

 ble.* This is remarkably exemplified in the beech and the 

 sycamore, and still more in the ash, of which the fibrous 

 roots sometimes amount to millions. Such soils, accordingly, 

 furnish the best rooting ground, and are always favourites 

 with the planter. To fit trees, however, for removal to situa- 

 tions of great exposure, the roots may, by artificial methods, 

 be multiplied to a degree far beyond what can be accom- 

 plished by unassisted nature ; and thus, by art discreetly 

 employed, the business of vegetation, that is, the circulation 

 of the sap, is prevented from standing still, during the ex- 

 treme violence, which transplanting in its best form must 

 inflict. 



Fourthly : Extent, Balance, and Closeness of Branches 

 Branches, like the roots and stem, are classed among the con- 

 servative organs. They are divisions of the trunk originat- 

 ing generally in the upper extremity, but often likewise 

 along the sides. The primary divisions are again subdivided 

 into secondary divisions, and these again into divisions still 

 smaller, till they terminate at last in slender sprigs or spra^. 

 In point of external form and structure, branches resemble 



* Du Hamel, Phys. des Arbres, T. I. p. 82.— Ellis, Veget. Anat. in 

 Supp. to Encyclop. Britan. 



17 



