10 A MANUAL OF THE CONlFiSKiE. 



the Order, but a few peculiarities that are met with in the. different 

 tribes require separate notice. . . 



In many of the species belonging to the Cypress tribe (Cupressmese), 

 and which are mostly of fastigiate or strict habit, the primary roots 

 lengthen but slowly, although they increase in thickness considerably 

 during the first years of the life of the tree; but the rootlets form a 

 dense plexus, occupying a circular area not much greater than the 

 spread of the branches above. It is not tiU the tree has acquired some 

 age, and the soil in immediate proximity to it has become quite 

 exhausted, that the roots lengthen to any considerable extent in search 

 of nutriment, which they do in conformity with a law universal 

 throughout the Vegetable Kingdom. The fibrous rootlets then become 

 more spreading ; those formed during the earlier life of the tree having 

 fulfilled their functions, die. 



In the Yew the plexus of fibrous rootlets is always very great even 

 at an advanced age of the tree, so that the absorbent power of the 

 roots of a large Yew must be enormous. There can be no doubt that 

 this is one of the causes that contribute to the longevity of the Yew; 

 and it is probable, too, that these rootlets have a limited power of 

 selection in the substances taken up by them, since the Yew will live 

 and thrive in soils of the most opposite description and maintain a 

 tolerably constant habit and colour of foliage everywhere. 



In the Sequoia tribe (Taxodise) all the principal members of which 

 are not only among the largest of Conifers, but also among the largest 

 of trees, the roots lengthen very rapidly from early life, and spread over 

 a large area always near the surface. A striking peculiarity is seen in 

 the roots of the deciduous Cypress (Tazodium disticlium) when this 

 tree attains its maturity and is growing in swampy places, as it most 

 commonly does in its native forests in North America, or in close 

 proximity to water in England; they form hollow conical or beehive- 

 shaped protuberances that rise several inches above the surface of the 

 ground, and which have never been noticed to produce buds from which 

 shoots proceed ; these protuberances are popularly called " knees."* The 

 deciduous Cypress will also send its roots deep down through water and 

 fix them into the soil beneath. 



Although under ordinary circumstances the roots of Coniferous plants 

 spread equally from all sides of the stem, they will, as in other plants, 

 develop in one direction more than in another when the nutriment 

 suitable for the support of the tree is present only on one side, or is 

 more abundant on one side than on others, or if they are prevented 

 by obstacles from extending equally on all sides ;t they will also grow 

 downwards to a considerable depth under similar influences, 



* See the article on Taxodium disticlium in Part II, with the engraving of the tree 

 with "knees," at Syon House. 



t See some remarkable instances of the rooting of the Spruce Fir in London. Arb. et 

 Frut., p. 2298. 



