30 MANUAL OP BOTANY 



protect them from the influence of external conditions, by 

 which they would otherwise be injured, or even destroyed. 

 Buds thus protected are sometimes termed scaly. In the 

 buds of tropical regions, and those of herbaceous plants grow- 

 ing in tenaperate climates which are not thus exposed to the 

 influence of a winter, such protective organs would be un- 

 necessary, and are accordingly absent, and hence all the 

 leaves of these buds are of nearly the same character. Such 

 buds are called naked. In a few instances we find that the 

 buds of perennial plants growing in cold climates, and which 

 are exposed during the winter, are naked like those of tropical 

 and herbaceous plants. Such is the case, for instance, with 

 the Alder Buckthorn (Bhamnus Frangula), and those of some 

 species of Viburnum. 



These protective organs of the bud are commonly, as we 

 have just mentioned, termed scales, but they have also received 

 the name of tegmenta. That such scales are really only modified 

 leaves adapted for a special purpose, is proved not only by their 

 position with regard to the true leaves, but also from the gradual 

 transitional states, which may be frequently traced from them 

 to the ordinary leaves of the bud. These scales have only a 

 temporary duration, falling off as soon as the growth of the bud 

 commences in the spring. 



The bud thus contains all the elements of a stem or branch ; 

 in fact it is really the first stage in the development of these 

 parts, the axis being hei-e so short that the rudimentary leaves 

 are closely packed together, and thus overlap one another. 

 When growth commences in the spring, or whenever vegetation 

 is reanimated, the internodes between the leaves become de- 

 veloped (fig. 38. rl, d, d), and these therefore become separated 

 from one another, c, c, c, and thus the stem or branch increases 

 in length, or a new branch is formed. In other words, the leaves 

 which in a- bud state overlap one another and surround a grow- 

 ing point or axis, by the elongation of the internodes of that 

 axis become separated and dispersed over a branch or an elon- 

 gation of the stem. 



It frequently happens that many of the lateral buds never 

 develop into branches. This is generally the case with those 

 which are produced in the axils of the lower leaves of the twigs 

 of most trees. Sometimes, though not developed at once, they 

 retain for years the power of growing into branches These 

 buds are called dormant buds, and the branches ultimately 

 arising from them are known as deferred branches, When 



