DICOTYLEDONE^E. 65 



art. The lately introduced Cunninghdmia was found 

 to strike roots by being- layered in the usual way ; 

 but these being the points of branches, such they 

 ever remained after being- separated from the parent 

 tree, and no confinement or training to a stake could 

 alter their horizontal tendency. To procure proper 

 leaders, therefore, the latent buds developed from the 

 collet, were only found to contain the natural struc- 

 ture of principal stems. 



It is not only in this instance we perceive the defi- 

 nite character in the structure of the regular grow- 

 ing Coniferce. Sometimes it unfortunately happens 

 that young firs and pines have their leading shoots 

 killed by a late frost in the month of May ; in which 

 case, no art of the nurseryman can avail to recover 

 the plants. They may continue to live, but never 

 regain their natural forms, unless they are cut over, 

 to induce the production of a shoot from the collet, 

 which very few will do. 



Notwithstanding this habitual regularity of growth, 

 we sometimes witness deviations from that sym- 

 metry which distinguishes so many of the Comferce. 

 Amongst the AbietincB or spruce firs, two or more 

 leaders are sometimes produced, which will grow up 

 together and share equally the central vigour and 

 perpendicular extension of the axis. The Pinu-s 

 strobus is often seen with a divided stem, especially 

 when advanced in years. Indeed the whole order, 

 after rising to their natural height, become bushy 

 headed ; the vigour of the axis appears then to be 

 F 



