ADVENTITIOUS BUDS 51 



promote the development of basal buds likely to become dor- 

 mant, but anything which impedes the movement of water or 

 ' flow of sap ' to the terminal and highly-placed buds tends 

 towards the same result. 



In the early formation of cordon fruit-trees, where it is important 

 that all the buds upon the main stem should develop shoots or 

 short spurs, bending the shoot for a time is practised in order to 

 promote the ' breaking ' of those buds at the base of the stem 

 which might otherwise remain dormant and leave a length of 

 unfruitful wood. 



15. Adventitious Buds. — Dormant buds, mentioned above, are 

 buds which have arisen in regular order in the axils of leaves, but 

 which have remained inactive some time ; the only irregularity 

 about them is their period of development. Buds may, however, 

 arise at any point of a plant, not necessarily in the axil of a leaf, 

 but on any part of the stem, or even upon roots and leaves : such 

 are termed adventitious buds. Examples are met with on the 

 roots of docks, poplars, roses, and many other plants, especially 

 when the upper bud-bearing parts have been removed. They 

 frequently arise and produce shoots upon stems which have been 

 injured. In some instances they proceed from the callus cover- 

 ing the wounds where branches have been cut oif ; some of the 

 shoots of ' pollard ' trees spring from adventitious buds originat- 

 ing in this manner. 



Adventitious buds are often produced upon leaves which have 

 been removed from the parent and pegged down on moist sand 

 or loam. Gardeners take advantage of this peculiarity in pro- 

 pagating begonias. 



Similar buds occur upon some kinds of leaves when they are 

 severed from the plant and their petioles stuck in moist ground : 

 the scales of the hyacinth and other bulbs give rise to new 

 plants in this manner. 



Ex. 21. — Examine twigs of ash, sycamore, elder, horse-chestnut, oak, 

 beech, and other trees and shrubs in winter. Make notes of the arrange- 



