684 



F A U J\l E R S ' REGISTER 



[No. 10 



ihe destruction or absence of leal-buds is accom- 

 panied b)' the absence of vvood: as is proved by a 

 shoot, [he up|)er bud of wiiich is destroyed, and 

 the lower allowed to develope. The lower partol 

 the shoot will increase in diameler: the upper will 

 ■remain of its original dimensions. 



102. The quantity of wood, therefore, depends 

 upon the quantity of leaf-buds that develope. 



103. It is of the greatest importance to bear this 

 in mind in pruning timber irees: for e.xcessive 

 pruning must necessarily be injurious to the (juan- 

 tity of produce. 



104. If a cutting wilh a leaf-bud on it be placed 

 in circumstances lilted to the developement of the 

 latter, it wiil grow and become a new plant, 



105. If this happens when the cutting is insert- 

 ed in the earth, the new plant is said by garde ne re 

 .to he upon its own botionu 



106. But if it happens when the cutting is ap- 

 plied to the dissevered end of another individual, 

 called a stock, the roots are insinuated into the tis- 

 sue of the stock, and a plant is said to be grafted, 

 the cutting being called a scion. 



107. There is, theretbre, liltle difference between 

 ■cuttings and scions, except that the former root 

 unto the earth, the latter into another plant. 



108. But if a cutting of the same plant, without 

 a leaf-bud upon it , be placed in the same circum- 

 stances, it will not grow, but will die. 



109. Unless iis vital powers are sufficient to 

 enable it to develope an adventitious leaf-bud. 

 (119.) 



110. A leal- bud separated from the stem will 

 •■also become a new individual, if its vital energy 

 iis sufficiently powerful. 



111. And this, whether it is planted in earth, 

 iinto which it roots, like a cutting, or in a new in- 

 dividual to which it adheres and grows like a scion. 

 In the former case it is called an eye, in the latter 

 a bud. 



112. Every leaf-bud has, therefore, its own dis- 

 itinct 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 collec- 

 tion of a great number of distinct identical sys- 

 tems of life, and consequently a compound indi- 

 •vidual. 



114. Regular leaf-buds being generated in the 

 ^axillaj of the leaves, it is there that they are al- 

 ways to be sought. 



115. And if they cannot be discovered by ocular 

 inspection, it may neverlheless be always inferred 

 with confidence that they exist in such situations, 

 anil may possibly be called from their dormant 

 state into lile. 



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 svstem 

 of lile which may be, by favorable circumstances, 

 called into action. 



117. Hence, all parts upon which leaves have 

 ever grown, may be made use of for purposes of 

 propagation. 



118. From these considerations it appears that 

 the most direct analogy between the Animal and 

 Vegetable Kingdoms, is with the Polypes of the 

 former. 



119. Adventitious leaf-buds are in all respects 

 like Regular leaf-buds, except that they are not 

 formed at the axilla^ of leaves but are developed 1 

 occasionally from all and any parts of a plant. | 



120. They are occasionally produced by roots, 

 by solid wood, or even by leaves and flowers. 



121. Hence roots, solid wood, or even leaves 

 and dowers may be used as means of propaga- 

 tion. 



122. Bu' as the developement of adventitious 

 buds is extremely uncertain, such means of pro- 

 pagation can never Lie calculated on; and form no 

 part of the science of cultivation. 



123. Tlie cause of the formation of adventious 

 leal-buds is unknown. 



124. From certain experiments, it appears that 

 they may be generated by sap in a state of great 

 accumulation and activity. 



125. Consequently, whatever tends to the ac- 

 cumulation of sap, in an active state, may be ex- 

 pected to he conductive to the formation of adven- 

 titious leaf-buds. 



V. £, eaves. 



126. Leaves are expansions of bark, traversed 

 by veins. 



127. The veins consist of spiral vessels enclos- 

 ed in woody fibre; they originate in the medullary 

 sheath and liber; and they are connected by loose 

 Parenchyma [7.] which is full of cavities contain- 

 ing air. 



128. This parenchyma consists of two layers, of 

 which the uj'per is composed of cellules perpen- 

 dicular to the cuticle, and the lower of cellules pa- 

 ralled with the cuticle. 



129. These cellules are arranged so as to leave 

 numerous open passages among them lor the cir- 

 culation of air in the inside of a leaf. Parenchy- 

 ma of this nature is called cavernous. 



130. Cuticle is formed of one or more layers of 

 depressed cellular tissue, which is generally har- 

 dened, and always dry and filled with air. 



131. Between many of the cells of the cuticle 

 are placed apertures called stumata, which have 

 the power of opening and closing as circumstances 

 may require. 



132. It is by means of this apparatus tha' leaves 

 elaborate the sap which they absorb ti-om the al- 

 burnum, converting it into ifie secretions peculiar 

 to the species. 



133. Their cavernous structure (129.) enables 

 them to expose the greatest possible surfiice of 

 their parenchyma to the action of the atmosphere. 



134. Their cuticle is a non-conducting skin, 

 which protects them from great variations in tem- 

 perature, and tiirough which gaseous matter will 

 pass readily. 



135. Their stomata are pores that are chiefly in- 

 tended to fiicilitaie evaporation; tor which they are 

 well adapted, by a power they possess of opening 

 or closinjj as circumstances may require. 



136. They are also intended for facilitating the 

 rapid emLssison of air, when it is necessary that 

 such a function should be performed. 



137. l^he functions of somata being of such 

 vital importance, it is always advisable to exam- 

 ine them microscopically, in cases where doubts 

 are entertained of the state of the atmosphere, 

 which a particular species may require. 



138. Leaves growing in air are covered with a 

 cuticle. 



139. Leaves growing under water have no cu- 

 ticle, 



no. All the secretions of plants being formed 



