THE SOUTHERX CULTIVATOR. 
63 
Horticultural Outline. | 
AN OUTLINE of the first principles of Houticulture, j 
by Jo ini Lind LEY, F R S. &c. &c., Professor ot^Bora- | 
ny in the University ot Loudon, and assistant Secre- 
tary of the Horticultural Society . — [continded ] 
III.— STEM. 
57. The stem i-s that part of the plant which j 
is developed above-ground, and which took an ; 
upward direction at the period of generation. j 
*5S. It consists ot a woody axis, covered by I 
barn having stomata (l3l) on this surface, j 
bearing leaves, with leat-buds in their axillae, | 
and producing flowers and truit. I 
59. The points where leaves are borne are I 
called IS'odi; the spaces between the leaves In- | 
ternodia. j 
60. The more erect a stem grows, the ^more ; 
vigorous it is ; an t the more it deviates trom | 
this direction to a horizontal or pendulous po- j 
sition, the less is it vigorous. 
61. Some stems are developed under ground, 
such as the Tabers of the Potatoe and the Co.“- 
mus of the Crocus; bat they are known from 
roots by the presence of leaves, and regular 
leaf-buds upon their surface. 
6‘2. Ste.ms increase in diameter in two ways: 
63. Either by the addition of new matter to 
the outside of the wood and the inside of the 
bark, when they are Exogenous ; ex. Oak; 
61. Or by the addition of new matter to their 
inside, when they are Endoginus; ex. Cane. j 
65. In Exogenous stems, the central portion, ] 
which is harder and daiker than that at the cir- 
cu.mference, is called while the ex- | 
terior, which is softer and lighter, is called Al- | 
burnuvi, or Sap-wood. I 
66. The inside of the bark of such stems has 
also the technical name of Liber. 
67. The Heart-wood was, when young, Al- 
burnum, and afterwards changed its nature, by 
becoming the receptacle of certain secretions 
peculiar to the species. 
63. Hence the greater durability of Heart- 
wood than of Sapwood. While the latter is 
newly formed, eraotv tissue, almost as perisha- 
ble as bark itself, the former is protected against 
destruction by the introduction of secretions 
that become solid matter, which is often inso- j 
iuble in water, and never permeable to air. 
69. The secretions by which Heart-wood is 
solidified are prepared in the leaves, whence 
they are sent downwards through the bark, and 
from the bark communicated to the central part 
of the stem. 
70. The channels through which this com- 
munication takes place, are called AlsdvJlary 
Rays or Silver grain. 
71. Medullary rays are plates of cellular tis- 
sue, in a very compressed state, passing from 
thf* pith to the bark. 
7'2. The wood itself is composed of tubes 
consisting of woody fibre and vascular tissue, 
imbedded longitudinally in cellular substance. 
73. This cellular substance only developes 
itself horizontally; and it is to it that the pecu- 
liar character of different kinds of wood is chief- 
ly due. 
74. For this reason the wood of the stock of 
a grafted plant will never become like that of 
its scion, although, as v.nM be hereafter seen,- 
(IV,) the woody matter of the stock irfust all 
originate in the scion. 
75. The stem of an exogenous plant may 
therefore be compared to a piece of linen, of 
which the weft is composed of cellular tissue, 
and the warp of fibrous and .vascular ti.ssus. 
76 In the spring and autumn a viscid sub- 
stance is secreted between the wood and the li- 
ber, called the Cambium. 
77. This Cambium appears to be the matter 
out of u hich the cellular horizontal substance 
-of the stem is organized. 
78. lii Indigenous stems, the portion at the 
circumference is hafder than that in the centre; 
and there is no separate bark, 
79. Their stems consist of bundles of woody 
matter, i nbedded in cellular tissue, and compo- 
sed of vat-cular tissue surrounded bv woody 
fibre. 
80. The stem is not only the depository of 
the peculiar secretions of species, (67,) bat this 
is also the medium through which the sap 
flows in its passage from the roots in the leaves. 
81. In Exogenous stems, (63,) it certainly 
rises through the alburnum, and descends 
through the bark. 
82. In Endogenous stems, (64,) it probably 
rises throogh the bundlesof wood, and descends 
through the cellular substance; but this is un- 
certain. 
83. Stems have the power of propagating an 
individual only by their Leaf-buds. If desti- 
tute of Leaf-buds, they have no power of mul- 
tiplication, except fortuitously. - 
IV. -LEAF-BUDS. 
84. Leaf-buds are rudiments of branches en- 
closed within scales, which are imperfectly 
formed leaves. 
85. All the leaf-buds upon the same branch 
are constitutionally and anatomically the same. 
86. They are of two kinds, viz : regular ov nor- 
mal. and adventilious or latent, (H9.) 
87. P>,egular leaf-buds are formed at the axil- 
lae of Leaves. 
68. They are organs capable of propagating 
the individual from which they originate. 
89. They are at first nourished by the ' fluid 
lying in the pith, but finally establish for them- 
selves a communication with the soil by the 
woody matter which the}' send downwards. 
90. Their foice of development will be in 
proportion to th'^ir nourishment; and, conse- 
quently, when it. is wished to procure a young 
shoot of unusual vigor, al! other shoots in the 
vicinity are prevented growing, so as to accu- 
mulate for one shoof only, all the food that 
would otherwise have been consumed by seve- 
ral. 
91. Cutting back to a few eyes is an opera- 
lion in prunihg, to produce the same effect by 
directing the sap, as it ascends, info two or three 
buds only, instead of allowing it to expend it- 
self upon ad the others which are cut away. 
’ 92. When leaf-buds grow, they develops in 
three directions; the one horizontal, the other 
upward, and the third downward. 
1 93. The horizontal development is confined 
[ to the cellular system of the bark, pith, and me- 
j dullary rays. 
I 94. The upward and downward develop- 
ments are confined to the woody fibre and vas- 
cular tissue. 
95. In this respect they resemble seed; from 
which they difier physiologically in propaga- 
ting the indi vidual, while seed can only propa- 
gate the species. 
96. When they disarticulate from the stem 
that bears them, they are called bulbs. 
97. In some plants, a bud, when separated' 
•from its stem, will grow and form a new plant 
(f placed in circunistances favorable to the pre- 
servation of its vital pov.'ers. 
98. But this property seems confined to plants 
having a firm, woody, perennial stem. 
99. Saehbuds, when detached from their pa- ! 
rent stem, send roots downvrards and a stem 
upwards. 
100. But it the buds are not separated from 
the plant to which they belong, the matter rhey 
send downwards becomes wood and liber, (56,) 
and the stems they send upwards become 
branches Hence it is said that wood and liber 
are lormed by the rco:s of ieaf-buds. 
Ifll. If no leaf-buis are called into action, 
there will be no addition of tvood; and conse- 
quently the destruction or absence of leaf-buds 
is accompanied by foe absence of wood; as is 
I proved by a shoot, the upper buds of which are 
destroyed and the lower allowed to dev'elopc. 
The lower part of the shoot will increase in di- 
ameter: the upper wili remain of its original 
dimensions. 
102. The quantity of Vvond, therefore, de- 
pends upon the quantity of the leaf-buds that de- 
velope. 
103. It is of the greatest importance to bear 
' this in mind in pruning timber trees : lor ex- 
cessive pruning must necessarily be injurious 
to the quantity of produce. 
104. If a cutting with aleaf-tud on it be 
placed in ci.rcumstances fitted tu the develop- 
ment of the latter, it will grow and become a 
new plant. 
105. If this happens when the cutting is in- 
serted in the earth, the new plant is said by 
gardeners, to be upon its oivn bottom. 
106. But if it happens when the cuttina is 
applied to the dissevered end of another indi- 
vidual, called a stock, the roots ate insinuated 
inm the tissue of the stock, and a plant is said 
to be grafted, the cutting being called a scion. 
107. There is, therefore, little difference be- 
tween cuttings and scions, except that the form- 
er root into the earth, the latter into another plant. 
103. But if a cutting of the sarnie plant with- 
out a leaf-bud upon it be placed in the same 
circumstances, it will not grow but will die 
109. Unless its vital powers are sufiicienl to 
enable it to develope an adventitious leaf-bud, 
(119.) 
110. A leaf-bud separated from the stem, will 
also become a new individual, if its vital ener- 
gy is sufficiently powerful. 
111. And this, whether itis planted in earth, 
into which it roots, like a cutting, or in a new 
individual, to which it adheres and grows like 
a scion. In the former case it is called o.n eye; 
in the latter, a t/nd. 
112. Every leal-bud has, therefore, its own 
distinct system of life, and of growth. 
113. And as all the leaf-buds of an individual 
are exactly alike, it follows that a plant is a 
collectmn of a great number of distinct identi- 
cal systems of life, and ci-nsequenily a com- 
pound individual. 
114. Regular leaf-buds being generated in 
the axillae of the leaves, it is there that they are 
always to be sought. 
115. And if they cannot bediscovered by ocu- 
lar in.^-pections, it may nevertheless be always 
inferred with confidence that they exist in such 
situations, and may possibly be called from 
their dormant state into life. 
116. Hence, wherever the scar of a leaf or 
the remains of a leaf can be discovered, there 
it IS to be understood- that the rudiments exist 
of a S3‘stein of life which may be, by favorable 
circumstances, called into action. 
117. Hence, all parts upon which leaves 
have ever grown may be made use of lor pur- 
poses of propagation. 
118. From these consideratione it appears 
that the most direct analogy between the ani- 
mal and vegetable kingdom is with the Poly- 
pus of the toTorer. 
119. Adventitious leaf-buds, are in all re- 
spects like regular leal-buds, except that they 
are not formed at the axilim of leaves but de- 
velope occasionally from all and any parts of a 
plant. 
120. They are occasionally produced by 
roots; by solid wood, or even by leaves and flow- 
ers. 
121. Hence roots, solid wood, or even leaves 
and flowers may be used as means of propaga- 
tion. 
122. But as the development-of adventitious 
buds- is exiremely • unceriai ; , such means of 
propagation can never be calculated on ; and 
form no part of the science of cultivation. 
123. The cause lor the formation of adventi- 
tiou- leal-buds is unknown. 
124. From certain experiments ft appears 
that they may be generated by sap in a state of 
great accumulation an i .activity. 
125. Consequently, whatever tends to th“ ac- 
cumulation otsap in an active state may beex- 
pected to be conducive to the formation of ad- 
ventilious leaf-buls. {Toie'-ontnuH'^ 
An* Acre. — An acre of land contains— 4 
roods, (or quarters,) each containing 40 poles 
or perches or rods; 160 rods, 18| leet each wav ; 
4,840 square yards of 9 leet each ; 43,560 square 
feet, of 144 inches each; 174 '240 squares of 6 
inches each, each containin? 36 inches; 6,272,= 
640 inches, or squares of one inch each. 
