BTTDS. 41 



scales, which affords an additional protection in the colds of 

 winter, as in the Willow, and many ethers. 



72. Buds, we remarked, were the rudiments of branches ; 

 but it sometimes happens, from some cause, that these branches 

 are not developed at all ; at others, they are only partly devel- 

 oped, receiving a check in their growth, and becoming thorns 

 and spines. The student may readily convince himself of the 

 fact, that thorns are partially developed branches, by observing 

 almost any thorny bush at different times. The Plum often 

 presents striking examples of it, on which the student may find 

 the branch in every state of development ; and the thorn of one 

 year may receive an additional impulse the next, and become a 

 branch. 



73. Since the development of buds produces branches, it is 

 plain that the arrangement of branches will be the same as that 

 of buds ; and as buds have their origin at the base of leaves, it 

 is equally plain that the branches of trees follow the same ar- 

 rangement as the leaves. If the leaves be alternate, the branches 

 will be so ; if opposite, the branches will have the same arrange- 

 ment. It happens, however, that by the non-development of some 

 of the buds, or the unequal elongation of the stem, the branches ex- 

 hibit some diversity ; but the reasons for any deviation may read- 

 ily be seen, having, as they do, their foundation in the above facts. 



74. Adventitious buds may have their origin in any point 

 where there is an anastomosis of woody fiber. (Lindley.) 

 Perhaps no subject in Botany has excited more interest, or has 

 more completely eluded the research of philosophers, than the 

 origin of adventitious buds. It is entirely removed from our 

 observation. Every part of a plant, from the root to the flowers, 

 seems to be endowed with the power, under certain circum- 

 stances, of developing buds; yet to determine the conditions on 

 which their development depends, has thus far baffled every 

 effort. Duhamel supposed that they had their origin from pre- 

 organized germs, which are deposited by the proper juice in its 

 descent from the leaves, and of course, pervade every part of the 

 plant. This is mere hypothesis, with not a fact to establish its 

 truth ; yet, as Mr. Nuttall remarks, it is impossible to prove its 

 falsity. Mr. Knight believed that they have their origin in the 

 alburnous vessels, which he supposed possessed the power of 

 generating central vessels, by which he means vessels of the 



72. Are the leaf-buds always developed? What do they become when 

 partly developed ? How may it be seen ? — 73. What must be the arrange- 

 ment of branches ? How is the diversity of branches explained ? — 74. 

 Where may adventitious buds have their origin ? Mention the theories on 

 this subject! 



