THE CONICAL GROWTH OF TREES. 61 



have an instance of branches which tend more to a cylindrical 

 than to a conical form. In consequence of this peculiarity, the 

 branches of this tree are long and pendulous, their water-fall-like 

 curvature is extremely graceful, and, as they wave backward 

 and forward in the wind, the tree presents one of the most 

 beautiful and picturesque of objects. 



But the conical growth of trees is sometimes strikingly appar- 

 ent in their landscape character, or general outline when viewed 

 from a distance. This is the case in the great Natural Order, 

 Conifers. The trees belonging to this order, such as (Juniper us 

 eommunis,) the common Juniper,(Juniperus Virginiana,) the Eed 

 Cedar, and the different species of Fir and Pine, when seen from 

 a distance, are clearly conical in their outline. This, in fact, is 

 more or less the original form of all trees in the first stages of 

 their development. For, at first, growth takes place principally 

 in the direction of the leading axis or stem, and the growth of 

 the branches is consequently greatly restricted ; but after a 

 certain number of years, the stem obtains its maximum elevation, 

 and growth is diverted to the branches. The tree then loses its 

 conical form and begins to spread out on all sides, forming, as 

 in the case of the Linden and Elm, a magnificent dome or crown. 

 In the Coniferse, however, development is not carried so far, and 

 the tree still retains its cone-like appearance through all the 

 stages of its life. For this reason, as well on account of the sim- 

 plicity of their flowers, these trees may be considered of a low 

 order of organization. 



The leaves of the tree are the true sources whence pro- 

 ceeds the elaborated formative material used in the building-up 

 of its stem and branches. Now, this law is plainly apparent in 

 the single axis, the structure of which depends on the manner 

 in which the phytons are superposed and combined, and in the 

 peculiar arrangement of the vascular bundles below them. The 

 phytons which produce the single axis are arranged spirally 

 around the axis in accordance with laws peculiar to each species. 



This spiral disposition of the leaves is a provision for securing 

 the symmetrical arrangement of the branches which proceed 

 from the buds in their axillae, and the uniform deposition of the 

 nourishing matter which proceeds from them around the axis. . 



