240 



DISEASES OF TREES 



habit of developing into dwarf shoots,* and consequently dormant 

 eyes are very scarce on these trees. In the case of old pines 

 only one or two buds remain dormant in each whorl, and in rare 

 cases a dormant bud may be perceived to burst forth at the base 

 of a shoot where the dwarf shoots (foliar spurs) are absent. 

 Should a pine be so injured, by the repeated attacks of cater- 

 pillars, that not only all the foliar spurs with their dormant 

 bu'ds but also the youngest shoots with their whorls of buds 

 wither, the only buds that the tree retains are the dormant 

 whorl-buds of the older shoots. These elongate to form the 

 so-called " Rosette Shoots," which however 

 are unable to preserve the life of the tree. 

 The rosette shoots either bear simple lance- 

 olate leaves alone, or along with these a few 

 foliar spurs. 



In the case of the larch only about 10 per 

 cent, of the leaves of the one-year-old shoots 

 have buds in their axils, all of which develop 

 to normal or dwarf shoots (leaf-fascicles). A 

 lost leader can be replaced only by the 

 vigorous development of one of these dwarf 

 shoots. 



The spruce and silver fir are also but 

 sparingly supplied with axillary buds, some 

 of which, however, remain dormant until 

 special circumstances stimulate them to shoot 

 out. These dormant buds are frequently to 

 be found in a whorl at the base of the annual shoot. 



The conditions under which dormant eyes may be stimulated 

 to form vigorous shoots vary, but all agree in this, that the buds 

 receive an accession of nutriment. As examples of stimulating 

 conditions I may mention pruning, coppicing, light-thinning, 

 defoliation by insects, late frost, &c> 



Adventitious buds are, generally speaking, comparatively 

 scarce. Their first inception is not in the axil of a leaf but at other 

 points of the stem, roots, or leaves, where they originate in after 

 years, and are therefore supplementary to the axillary buds. 



* [e.g. The pairs of leaves 0:1 a Scotch or Austrian Pine arise each on such 

 a dwarf shoot or "foliar spur." ED.] 



FIG. 137. Globular 

 shoot ("sphere- 

 blast ") of a beech 

 which has been 

 formed from a 

 dormant eye after 

 the latter had be- 

 come disconnect- 

 ed from its vas- 

 cular bundles. 



