MIXED CBOP OP TJNirOBM AflTS. 73 



come latent. Amongst our broad-leaved trees and shrubs there ia 

 none but in which a large proportion of the buds formed each year 

 become dormant and even latent. 



At first we will consider the difference in the number and vigour 

 of the dormant buds only as regards the various individuals be- 

 longing to one and the same species. This difference will depend 

 on — 



(i) The origin of the plants. — Size for size, young plants ori- 

 ginating directly from seed will, under average conditions, gener- 

 ally possess more dormant buds than stool-shoots and suckers, and 

 stool-shoots more than suckers. The superiority of seedHng plants 

 is due not only to their greater age and the relatively restricted 

 development of their crown, implying the unfolding of a smaller 

 proportion of the buds produced, but also to their better general 

 health, their shorter and therefore, size for size, more numerous 

 intemodes, and the greater thinness of the dead bark covering 

 their stems. Plants on stools are better off than suckers principal- 

 ly because ofthe sudden arrest of vegetation that always follows upon 

 the exhaustion of all the reserve food stored upin the parent stools, 

 especially if they have come up in clumps, and also because of their 

 more knotty development. With advancing age, the advantage 

 possessed by seedUng plants increases, for, except under adverse 

 conditions, they are always much more healthy and vigorous, pro- 

 duce more numerous twigs and small branches, and, therefore, also 

 more buds, and are longer lived. The difference between stool- 

 shoots and suckers is soon lost with age. Pollards, which are al- 

 ways very rich in dormant buds, have been excluded from consi- 

 deration here, since they are really mutilated individuals, that is to 

 say, individuals not growing under normal conditions. 



(ii) The age of the plants. — ^A plant that has just come up, can- 

 not, from the very nature of the case, possess dormant buds; but as 

 it grows on, provided, it is not against the nature of the species to 

 possess such buds, a certain proportion of tiie buds produced during 

 each growing season must remain tmdeveloped and become dor- 

 mant; and this proportion increases in geometrical progression, as 

 a result not only of the rapidly expanding crown, but also of the 

 multipUcation by divison of pre-existing dormant buds. Thus each 

 successive year adds a larger and larger quota to the ever-swelling 

 number of dormant buds in the tree or shrub. This steady aug- 

 mentation goes on all through the phase of longitudinal growth, 

 while the development ofthe crown is comparatively restricted, 

 and even continues during the early part of the phase of lateral 



