44 



THE BOOK OF NATURE STUDY 



look at it under the microscope. In the Ash, two compound leaves, 

 each having seven leaflets, will be seen in the centre opposite 

 each other. The next two leaves are at right angles to those, the 



next two to the second pair, 

 and so on until the four outer 

 scales are reached. The 

 accompanying figure shows 

 the arrangement in the bud 

 of the Sycamore. 



In spring, as soon as the 

 scales burst and the foliage 

 begins to open out, the inter- 

 nodes of the stem grow 

 longer and longer, giving 

 rise to the "long-shoots " at 

 the apex of the twig. As 

 the shoot elongates, buds 

 begin to be formed in the 

 axil of the leaves. Towards 

 the end of the summer these 



buds may be seen, and when the leaf falls off in the autumn, 

 leaving its scar behind it, the buds are prominent. In the 

 following spring the apical or the topmost lateral bud develops 

 into the new shoot. Meanwhile in the winter it is protected 

 from wet and cold by the scales, downy hairs, resin, etc., already 

 mentioned. 



FlG. 27. Bud of Sycamore, transverse section. 

 Bud scales on the outside, and foliage leaves 

 in the centre. 



ADVENTITIOUS BUDS. Sometimes buds develop without any 

 definite relation to the leaves; these are called "adventitious" ; 

 they are, as it were, accidental or accessory. The buds that appear 

 on the wounded edges of a begonia leaf when it is sliced and 

 pinned down on damp sand, is a case in point. Under abnormal 

 circumstances buds may develop even on roots and give rise 

 to leafy or even flowering shoots, as in the Hawthorn. 



The study of buds affords considerable material for practical 

 work. About March or April, or even earlier, twigs of different 

 trees may be examined and the position of the buds noted. Then 

 the nature of each bud should be determined, whether it will 



