ao6 



FARMERS' REGISTER 



[No. 4 



each other; and if the barks are of different 

 thicknesses, the inner surfaces, and not the outer 

 must coincide. This is evidently necessary, in or- 

 der that the "leaf-roots" growing down between 

 the bark and the wood of the graft, may enter be- 

 tween the bark and the wood of the stock. Ano- 

 ther rule is, that both in budding and grafting, we 

 must place the bud or graft upon a stock which 

 has a bark similar to its own, and upon no other. 

 By a similar bark, we mean one which has the 

 fibres of its fibro-vascular system arranged in the 

 same way. If these fibres lie parallel in the bark 

 of one, they must lie parallel in the bark of the 

 other ; if they cross each other in one, they must 

 cross each other in the other also. Thus, we may 

 graft a pear upon an apple stock, or an apple upon 

 a pear stock ; but neither of them upon a peach 

 stock. We may bud a peach upon a plum, or a 

 plum upon a peach ; but neither of them upon an 

 apple. If we graft a shoot, the fibres of whose 

 bark lie parallel to each other upon a stock the 

 fibres of whose bark cross each other, the fibres 

 of the former in growing down among those of 

 the latter, become entangled and cannot proceed 

 far. Another rule is, to graft or bud belbre the 

 leaves have put forth. The reason lor this rule is. 

 that then the roots from the new leaves have 

 not as yet put forth, and of course are not m- 

 jured. 



Such are some of the facts by which this theory 

 is supported ; and such are some of the applica- 

 tions which may be made of it, for the purpose of 

 explaining phenomena presented in the vegetable 

 kingdom. Still it must be confessed that the ar- 

 guments in its favor, are not so convincing as could 

 be desired ; and moreover that there are some ob- 

 jections to it, vvhich do not admit of so satisfacto- 

 ry an explanation, as those already mentioned. 

 One of these, and the most weiirhty one too, is, 

 that when a deep cut is made into one side of a 

 tree, the leaves which are perpendicularly above 

 it, do not always, or even generally, die. Nor if 

 after the leaves are fairly formed, each one has its 

 own proper root, extending down into the ground, 

 we must of necessity, in cutting into the tree, cut 

 off the roots of many of ihem ; and their life 

 should be destroyed as the consequence. The 

 only answer which can be given to this, is, titat 

 although in ordinary circumstances, each leaf is 

 sustained by its own roots or fibres, yet, in extra- 

 ordinary circumstances, it may derive its nourish- 

 ment from the soil, through the intervention of 

 those of other leaves. Or, carrying out the figure 

 which Da Petit Thouars has used, in calling a 

 tree a community of leaves, although each leaf, 

 while hale and sound, must labor for its own sub- 

 sistence, yet when injured or disabled in any 

 way, it is supported by a tax levied upon its neigh- 

 bors. 



This theory, if we adopt it, will present the ve- 

 getable kingdom to us in a light very diHerent 

 from that in vvhich we are in the hahit of regard- 

 ing it. We can no longer look upon a tree as an 

 individual in that kingdom ; so far is it liom bein<r 

 such, that it is in fiict, a vast collection of indivi- 

 duals, all united under one common cover, and for 

 one common purpose. Each generation of leaves, 

 borne up upon the shoulders of those preceding it, 

 is raised into the air, and better filled for perform- 

 ing its vital flinctions. This subjecl is one which, 

 among botanists, is exciting a good deal of inter- 



est at the present time. Ic is always pleasant, and 

 generally profitable, to know what are the current 

 subjects of investigation ; even though but little 

 is, as yet, known respecting them ; to see in what 

 direction mankind are pushing their discoveries, 

 even though ihey have, as yet, proceeded but a lit- 

 tie way. This must be my apology for occupying 

 so much space as 1 have, with a discussion of 

 these theories. 



Chap. VTII. 



leaves. their general, structure. ar- 

 raisgement of the cellular and fi- 

 bro-vascular systems in the leaf. of- 

 fice of the leaf. jhsposition of leavi39 

 on the stem. fall of the leaf. 



The third, and last, of the organs of vegetation, 

 are the leaves. In examining litis class of organs, 

 the same order will be preserved, as in the case of 

 the root and stem ; attending, first, to their exter- 

 nal forms and internal structure, and then to their 

 uses and manner of growth. 



The leaf^ like the root and stem, consists of a 

 cellular and of a fibro-vascular system, entirely 

 distinct from each other ; the latter, forming what 

 has been termed the skeleton of the leaf; the other,^ 

 like the flesh in the human body, lying upon this 

 skeleton, and filling up its interstices. The fibro- 

 vascular system, composes what are called the 

 veins, and sometimes, though very improperly, 

 the nerves, of the leaf The cellular system forms 

 the fleshy part, or, as the botanists call it, the pa- 

 renchyma of the leaf The tubular vessels, and 

 woody fibre, enter the leaf at its extremity near- 

 est the stem, technically called its base, in a few 

 distinct bundles ; but soon after, these bundles di- 

 vide and sub-divide, until at length, not more than 

 two vessels are left together ; one for conveying 

 the sap, in its crude stale, out from the stem_ ; the 

 other tor returning it to the stem, after it has un- 

 dergone certain changes in the leaves. 



Leaves are arranged m classes by botanists, ac- 

 cording to the manner in which the fibro-vascular 

 system is disposed throughout the parenchyma. 

 The principal of these classes are, 1st, that in 

 vvhich the bundles of fibres, after entering toge- 

 tiier, at the base of the leafj diverge, and their sub- 

 divisions in no instance cross each other. Of this 

 class the leaves of the red maple (acer rubrum) 

 afford an example. Such leaves are said to be 

 radiant-veined; and sometimes, fork-veined. 2d., 

 that in which the primary veins diverge from the 

 main vein, or mid-rib, like the plumes of a feather. 

 Of this structure, the leaves of the chesnut and 

 chinquapin (^castnnea vcsca and pumila) are in- 

 stances. Such leaves are called leather- veined 

 leaves. 3d, that in which the several veins pro- 

 ceeci without branching, from their origin at the 

 base to their termination at the apex of the leaf 

 The veins, in such leaves, are connected by minute 

 veinlets, passing at right angles from one to the 

 other. The leaves of grasses belong to this class. 

 Such leaves are called parallel veined leaves. On 

 examination, it will be found that almost all 

 leaves have their fibro-vascular system arranged 

 in one of these three ways; and tiirther, that the 

 vast variety of form which we notice in the 



