1839] 



FARMERS' REGISTER 



66 



does fumiili itself with adventilious roots. It is 

 well known, that when the trunk of a Lombardy 

 poplar (populus dilatata) is cut off near to the 

 ground ; and even in some iiislunces, wlvere the 

 trunk is not cut off, but parts of its roots project 

 above tlie surface, (hose roots will produce buds 

 and youn^ shoots, in abundance. It is also well 

 known, that if a stalk of the weeping-willow (sa- 

 lix babylonica) be cut oti, and stuck in moist 

 ground, it will soon form adventitious roots, and 

 become a tree as readily as if raised from the seed. 



Du Hamel perlbrmed a singular experiment 

 upon a young willow. He bent the trunk, so as 

 to bury the extremities of the branches in the 

 ground; after these had taken root, and had es- 

 tablished themselves in their new situation, he un- 

 covered the true roots, and elevated them into the 

 air ; thus turning the tree upside down. The 

 roots, adapting themselves to their new situation, 

 produced buds and leaves; whilst the Ibrmer 

 branches took the place of roots. We must not, 

 however, infer from this, that roots and branches 

 are mutually convertible into each other. The 

 branches in this ease were not changed into roots, 

 by being buried in the earth, nor even the roots 

 changed into branches, by being elevated into the 

 air ; but the buried branches, gave rise to adven- 

 titious roots, whilst the roots, in the new and ex- 

 traordinary circumstances, in which they were 

 placed, gave rise to adventitious buds. This pow- 

 er o( forming adventitious buds, is peculiar to the 

 roots of some plants, and not common to those of 

 all. The roots of the silver fir of Switzerland, 

 will sometimes live for half a century after the 

 stem is destroyed, but will never sprout again ; 

 whilst the roots of the Lombardy poplar, will put 

 forth buds almost as readily as the stem itself 



A third distinction between the root and the steni 

 is to be found in the manner of their growth ; the 

 stem always maniiesting a tendency to grow with 

 perfect regularity, vvhilsf the root never docs. In 

 this particular, the stem and the root are admirably 

 adapted to the different media in which they de- 

 velope themselves. Burrowing beneath the soil 

 as the root does, and having to niake its way in an 

 unequally yielding medium, now having its pro- 

 gress stopped on one side by a rock or some other 

 hard substance, and then on the other side, it 

 would have been impossible lor it to have grown 

 with perfect regularity, even had provision been 

 made for such a growth. But not so with the stem; 

 shooting as it does up into the air, it can increase 

 equally well in every direction. II we examine 

 a young shoot of any plant, as the dog-wood 

 (corftKS sanguineus') lor instance, at the close of 

 its first year's growth, we will find its leaves dis- 

 posed with perfect regularity. In the plant select- 

 ed they are placed in pairs, and regularly alternat- 

 ing with each other, as to the sides of the stem on 

 which they grow. If the first pair point north and 

 south, the second will point east and wesi, the third 

 north and south again, and so on. The buds, 

 which are in fact the ruilimentary branches of the 

 next year, are formed only at the points at which 

 the leaves are joined to the stem, and of course 

 must be placed on that stem with the same perfect 

 regularity wliich characterizes the disposition of 

 the first year's leaves. The same remarks will 

 apply to the branches ol'each succeeding year. If 

 a plant could grow, entirely exempt from the ope- 

 ration of all disturbing causes, it would be as per- 



fectly regular as if put together by the hand of 

 art, with the square and compass. The only rea- 

 son why plants never do present this appearance is, 

 that they always are affected, more or less, by cer- 

 tain external causes, which disturb their growth. 



I will mention some of these disturbing causes, 

 and illustrate their operation. We will suppose that 

 a plant, during the first year of its life, has formed 

 eight buds, and that each of these is packed away 

 under its shealh of scales, in order to stand the 

 storms of winter. The sheaths are seldom so form- 

 ed as to be a perfect protection against water. It 

 is almost always the case, that if a drop of rain 

 happens to strike them precisely upon the tip, it 

 will penetrate into the bud. If after such an acci- 

 dent has happened, a cold night occurs, this water 

 will freeze, and thus, the bud, and all that in other 

 circumstances would have sprung from it, will be 

 destroyed. It frequently happens, that of the buds 

 formed one season, not more than one-half live to 

 open and grow the next spring. Now, it is very 

 improbable, that if one-half of eight buds be tlius 

 destroyed, they will be either the first, third, fifth, 

 and seventh, or the second, fourth, sixth and eighth; 

 and yet all these would be necessary in order that 

 the plant may retain a perfect regularity of form. 



Again : there are many insects which by instinct 

 are taught to pierce the stems of plants in order to 

 deposite their eggs. Whenever this is the case, 

 the part thus pierced swells up, and disorganiza- 

 tion, to a greater or less extent, ensues. The nut- 

 gall, the green balls which we often see on the 

 leaves of the oak, and the excresences which we 

 see on the stems of plants, are all produced in this 

 way. If we suppose that the wound inflicted by 

 the insect exerts no positively deleterious influence 

 upon the growth of the plant wounded, yet, as an 

 excrescence is formed, a part of the nutritious mat- 

 ter, which, in ordinary circumstances, would have 

 gone to increase the size of the limb, is necessarily 

 employed in the formation of the excrescence; and 

 of course the limb must suffer in size on this ac- 

 count. Thus, an irregularity in the form of a plant 

 may be produced. 



Again: we know that direct sun-light is neces- 

 sary to the heaUhy growth of a plant. So soon 

 as a tree has grown to some considerable height, 

 its upper branches shade those beneath them, and 

 thus induce in them a diseased growth, and even 

 death itself. All are familhar with the fact, that 

 what is commonly called the trunk of a tree, sel- 

 dom presents any branches. This is not because it 

 did not send out branches in the first instance, but 

 because the branches which it did form have been 

 overshadowed and destroyed by those growing 

 higher up upon the stem. In the case of a spe- 

 cies of pine common in lower Virginia, the branch- 

 es of which are early filled with resin, and on that 

 account do not easily decay, a scries of dead 

 branches may be seen stretching from the root up 

 to the living branches of the tree. Trees growing 

 in the forest, where they ate shaded by the sur- 

 rounding trees, seldom present many lateral 

 branches, except towards the top ; whilst those 

 growing in the open field, where the sun-light has 

 free access to them on every side, generally spread 

 their branches far and wide. 



Again : a young shoot may be bent by the wind; 

 if bent but little, its elasticity will generally restore 

 it ; but, if bent much, it receives a permanent 

 crook, and thus an irregularity is produced. The 



