PLANTING. 3 



judicious and successful manner. This part of the subject properly belongs to 

 vegetable physiology ; and as the limits of an essay do not allow of entering 

 into minute details, we shall here only notice those leading features of the 

 structure of trees, and those functions of their vital organs, which more 

 immediately influence the practical operations of the planter. In con- 

 sidering the progress of vegetable life, physiologists have distinguished 

 six principal parts of a tree : the root, the stem, the branches, the leaves, 

 the flowers, and the fruit or seed. 



The varieties of the root of forest-trees are characterised by the names 

 of tap root, fibrous root, and creeping root, these maybe considered rather 

 as indicating particular states of the same organ at different stages of 

 growth than as permanent or specific distinctions *. 



The tap root is that which first appears on the vegetation of a healthy 

 seed, and penetrates perpendicularly into the soil. From it issue nu- 

 merous minute radicles ; and as the proper leaves are developed, lateral 

 roots or fibres are formed and sent out from the sides of the tap root, 

 particularly at the point of junction situated between the radicle and stem. 



As the plant advances in age the distinction of the tap root is lost, either 

 by decay or by its taking a horizontal direction in common with the 

 general mass of roots, and from which in a few years it is not to be 

 distinguished. Other leading roots are frequently formed from the first 

 delicate lateral fibres, which pervade the tap root, and sometimes from its 

 extremity when it happens to divide into parts, which always takes place 

 when the extremity comes in contact with a richer or more genial soil, or, 

 on the contrary extreme when it meets with obstructions in its first or 

 early descent from whatever cause, rocks, gravel, &c., or by injury from 

 insects : if the tap root be taken from the seed leaves before the plumula 

 appears, or before the development of the proper leaves, the young 

 seedling dies ; and, again, should the tap root be deprived of the seed leaves 

 before the production and expansion of the proper leaves, no farther 

 reproduction or growth takes place. The uses of the tap root, it will 

 readily be perceived from these facts, are of great importance to the plant 

 in its first stages of growth, and may be compared to the equally essential 

 and important uses of the seminal leaves, at the same period; but its 

 subsequent destruction does not, as it has been supposed, influence 

 injuriously the ultimate produce or value of the tree. 



Two or any equal number of trees, for instance, of the same age, of the 

 like constitution, and reared on a soil of the same nature, the one from 

 seed on the spot, the other being transplanted from a nursery bed, without, 

 or with a portion only of its tap-root, will give results which prove that 

 trees, when transplanted at a certain age and size, and in all other respects 

 of culture under the same circumstances, produce timber in quantity and 

 in quality equal, if not superior to untransplanted seedlings. Whether, 

 therefore, to raise forest-trees from seed on the spot where they are to 



* In practical planting, as well as in practical botany, the root is considered to be that 

 part of a plant which is hid underground, and the varieties of it are characterized ac- 

 cording to the shape and mode of growth, as bulbous, tuberous, fibrous, or creeping; 

 these again are susceptible of subdivision as they vary from the type. In physiology, 

 however, the fibres or radicles are alone recognised as the roots, as it is they only which 

 take up the food of the plant supplied by the soil. 



The tuber of the turnip, potato, &c. and the bulb of the hyacinth, &c. are properly 

 reservoirs in which to deposit the food of the plant until wanted in season for the pro- 

 duction of leaves, flowers, and fruit, or seed. Indeed, bulbs and tubers may be considered 

 the plant itself in certain stages of its progress to maturity. A deciduous forest-tree in 

 winter, when without its leaves, flowers, and seed, may be compared to a bulb or tuber, 

 when destitute at the same time of these parts of a plant. Roots, in general, are also 

 distinguished in practice as to duration, being annual, biennial, and perennial. 



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