IV] SPIRAL ARRANGEMENT OF BUDS 33 



the oblique or horizontal position of the branches, as they 

 grow on the tree, but no satisfactory explanation exists to 

 account for it. 



Much more common is the spiral arrangement of 

 alternate, as contrasted with opposite, buds and leaves. 

 It prevails in 



Alder Robinia Barberry 



Walnut Alder Alder Buckthorn 



Willows Black Currant Red Currant 



Gooseberry Poplars Oaks 



Roses Sweet Gale Mulberries 



Blackberry Apple Pear 



Laburnum Sea Buckthorn Plum 



Almond Hawthorn Cherry 



Furze Blackthorn Bird Cherry 



and indeed in the majority of other trees and shrubs. 



The commonest spirals in our native trees and shrubs 

 are f and f, but ^ is not rare and may even occur 

 simultaneously with f . But considerably higher numbers 

 may prevail, and the scales on a cone of the Silver Fir 

 may be ^ 8 T . 



A somewhat curious state of affairs, as expressed 

 sometimes in the branching, results from the habitual 

 presence of two or more buds in some of the leaf-axils. 

 In some cases the accessory buds as the extra buds are 

 termed are found side by side, e.g. in Symphoricarpos 

 racemosa, where there is usually one small bud on each 

 side of the larger, or dominant, primary axillary bud, and 

 evidently each developed in the axil of the lower bud- 

 scale on its side. This is contradictory of the general rule 

 that bud-scales are devoid of axillary buds. Other cases 

 of collateral accessory buds are found in the Elder and in 

 the allied Sambucus racemosa, sometimes accompanied by 

 a lower bud as well, and in certain Jasmines and Maples, 

 w. i. 3 



