96 



THE planter's guide. 



tion of the sap — is preyented from standing still dui'ing 

 the extreme violence which transplanting, in its best form, 

 mnst inflict. 



Fourthly. — Extent, balance, and closeness of branches. 

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

 conservative organs. They are divisions of the trunk, 

 originating 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 twigs or spray. In point of external form and 

 structm'e, branches resemble the trunk from which they 

 issue ; but in point of insertion, distribution, and direc- 

 tion, they exhibit considerable variety, furnishing a ground 

 of distinction occasionally assumed by botanists in the 

 discriminating and characterising of species. Like the 

 stem and root, branches increase in width by the accession 

 of new layers, and in length by tlie addition of new 

 shoots ; but they are not formed merely by means of an 

 horizontal extension of the longitudinal tubes of the 

 stem, but each branch is, as it were, a distinct individual. 

 Hence the stem is to the branch what the soil is to the 

 plant — the source of nourishment and stability.* 



Branches may properly be considered as among the 

 most important parts of trees, as they certainty are the 

 most beautiful. One of the most obvious offices they 

 have to perform is to support the leaves ; and the leaves, 

 by a respiration perceptible and imperceptible, and by 

 the action of the atmosphere, as above noticed, elaborate 

 the sap sent up by the roots, and convert it into juice 

 fitted for nutrition. The ascent of the sap from the roots 

 seems to be considerably assisted by a proper number of 



* Grew, Anat. of Plants, p. 28. Du Hamel, torn. i. p. 93. Keith, vol. i. pp. 

 48-51 ; vol. ii. pp. 255, 256. 



