88 Principles of Plant Culture. 



stem, they may under the stimulus of unusual root pres- 

 sure (101) be formed without regard to nodes. The 

 trunk of a vigorous elm, willow or horse-chestnut tree, 

 cut off early in the season, often develops a multitude 

 of buds from the thickened cambium (68) at the top 

 of the stump, and a circle of shoots often spring up 

 about the base of a tree of which the top has been in- 

 jured by over-pruning or severe cold. Such buds are 

 called adventitious. It is, however, often difficult or 

 impossible to distinguish between adventitious buds and 

 those that have been previously overgrown (129). 



The roots of many plants, as the plum, choke cherry, 

 raspberry, etc., develop adventitious buds freely, espe- 

 cially when injured, a fact often utilized in propaga- 

 tion by root cuttings (376). 



131. Leaf-Buds and Flower-Buds. Buds may con- 

 tain only rudimentary leaves, or they may contain rudi- 

 mentary flowers, with or without leaves. The former 

 are called leaf- or wood-buds, the latter flower- or fruit- 

 buds. Flower-buds are modified leaf-buds. Both origi- 

 nate in the cambium layer (68) arid are normally 

 located at the apex of the stem or in the axil of a 

 leaf (127-128). 



132. Flower-Buds are often Readily Distinguished 

 from Leaf-Birds by location and appearance the same 

 season in which they are formed, which enables the fruit 

 grower to anticipate his crop. In the peach and apri- 

 cot, and in many varieties of plum, a flower-bud is 

 normally formed on each side of the leaf-bud in the 

 young shoots of bearing trees (Fig. 37). In the apple 

 and pear, the flower-buds are less definitely located, 



