33 



same object may be attained by different plants in entirely 

 different ways. Thus one plant may obtain the best illumi- 

 nation for its foliage b} T heterophylly, another by adopting 

 a different arrangement of the leaves upon the stem, or by 

 varying the lengths of the petioles, another by adopting a 

 climbing habit, and so on. 



32. Buds normally arise in the Eud8 - 



leaf axils, or at the apex of the stem or branches. Those 

 arising elsewhere are adventitious. Some buds contain only 

 rudimentary foliage leaves, others rudimentary flowers and 

 some both rudimentary leaves and flowers. 



If we examine an ordinary foliage bud, especially when 

 it is bursting into vigorous growth, we can easily satisfy our- 

 selves that it is merely a young stem, or branch, bearing the 

 as yet imperfectly developed leaves and with very short inter- 

 nodes. 



Some buds are covered with dry scales which protect the 

 delicate young parts within them from being dried up and 

 killed; these are well seen in the large buds of the Horse Chestnut, 

 Aesculus indica. The bud is often still further protected by a 

 coating of wax, gum, or resin, while the young parts inside the 

 scales are also often protected by a covering of wool, or hair. 

 Other buds have no protecting scales and are said to be naked, 

 e.g. those of Teak. If we watch the development of a scaly 

 bud we find that, shortly after the bud opens and begins to 

 grow vigorously, the scales which previously covered and pro- 

 tected it fall off, leaving behind several small scars close 

 together on the stem, indicating the spots where they were 

 inserted. These can be well seen in Fig. 1, Plate VII, which 

 shows a twig of Acer caesium from the terminal bud of which 

 4 leaves have developed, the bud-scales having just been shed. 

 In all trees and shrubs therefore in which the growth of stems 

 and twigs is stopped once annually, scaly buds being produced 

 at their apices during the period of rest, it is clear that we . 

 can calculate their age, so long as these scars of the bud-scales 

 are visible. In Fig. 1, Plate VII, for instance, the twig 

 shows the completed growth of 3 years, while that of the 4th 

 year has just commenced. In the spruce, Picea Morinda, the 

 bud scales do not fall off singly, but cohere, ac.d are carried 

 up like a cap on the tip of the young expanding shoot. 



In connection with this question of the age of shoots should 

 be noted also the fact that in Pines one whorl of lateral 

 branches is usually developed each year, so that the age of 



