THE .KOOTS. 



- 7 



at the apex in Picea. In the three- and five-leaved species of Piims 

 the cotyledons, like the foliage leaves, are three-sided and terminate in 

 a sharp point, the outer side rounded and green, and the inner sides 

 flat and glaucous. In Ginkgo they are thick, fleshy, oblong, contracted at 

 the base into a short stalk, leaving the endosperm enclosed within the shell. 



THE EOOTS. 



THE radicle, or primary root of the seedling plant, is slender and 

 descends straight downwards into the soil, and, as it lengthens, gives 



off fibraline rootlets that are often arranged 

 in two ranks ; but in many cases they are 

 scattered or given off at irregular intervals. 

 As the growth of the axis proceeds, the 

 changes that take place in the size and direction 

 both of the primary root and its branches are 

 greatly influenced by the circumstances of 

 -e soil and other conditions under which the 

 plant is growing. In species of the Fir and 

 Pine tribe that have their home on the slopes 

 of lofty mountains and on hill-sides that are 

 constantly undergoing denudation by the weather, 

 or where the soil is very shallow or only 

 accumulates in hollows or crevices of the 

 rocks, the downward course of the primary 

 root is soon arrested ; but the secondary roots 

 increase in diameter and lengthen greatly, 

 creeping over the surface of the ground to a 

 great distance, sometimes to such an extent as 

 to excite the surprise of the beholder.* But 

 in the plains where the soil is deeper and 

 the sub-soil more or less penetrable, a decided 

 tap-root is often developed from the primary 

 radicle which descends vertically to a 

 considerable distance or till it meets with 

 some obstacle to its progress. Instances of 

 this are seen in several of the Pines planted 

 for purposes of utility, as Pinus Pinaster on 

 the sand-dunes in the south-west of France ; 

 P. Laricio nearly always, whence this Pine is 

 sometimes difficult to transplant ; Taxodium distichum likewise sends 



* Among some remarkable recorded instances may be noted the Araucarias on the 

 rocky slopes of the Andes of Southern Chile, the roots of which have been compared 

 to gigantic serpents ; Abies bracteata on the summits of the Santa Lucia in South 

 California ; the Larch and Mountain Pine on the Tyrolese Alps ; the red and white 

 Pines of Japan which escape destruction by growing on inaccessible rocks on the central 

 mountain chain, where their roots are said to spread to a prodigious distance. 



Fig. 4. Seedling plant of Ginkgo 



h Unix!,. c, cotyledon ; p, 



primordial leaf. 



