66 



the circumferouco towards the centre ; that there arc usually 

 three or four and sometimes five or six such perpendicular roots ; 

 tliat their terminations are always composed of delicate tubular 

 cells joined end to end, and arranged parallel to each other and to 

 tlie long axis of the root, and that these roots are always ar- 

 ranged strictly parallel to the medullary rays of the nourishing 

 plant. "The young cellular root of viscum may be regarded 

 generally as a prolongation of the central pith of the parasite, 

 and contiguous mcduUary rays of the nourishing plant are suc- 

 cessively confluent with its surface." 



Having minutely described the loose porous structure of 

 the stem and base of the Mistletoe, De. Harley says "with re- 

 gard to the direction and arrangement of the roots of the Viscum 

 which lie within the wood, this is determined by the arrange- 

 ment of the medullary system of the nourishing plant, the roots 

 always lying strictly parallel to the medullary rays ;" a conclu- 

 sion to which he was led by the fact, that the Mistletoe and the 

 supporting branch grow at right angles to each other, and that 

 on a transverse section the Mistletoe roots are always shown to 

 be arranged like the radii of a circle from the circumference 

 towards the central pith. 



"The horizontal ramifications (side roots) of the base of the 

 Mistletoe have plainly the same structure as the young per- 

 pendicular roots. Whichever direction they take, they produce 

 at frequent and pretty regular intervals, other tapering cellular 

 roots which guided doubtless by the medullary rays of the bark 

 press towards the surface of the wood and are thus brought in 

 contact with the ends of its meduUary rays. They are sub- 

 sequently found embedded at various depths in the hard wood 

 of the nourishing plant, like the primary roots. These lateral 

 roots also give origin to budlike processes, which, deepening in 

 colour, grow up obliquely through the bark, and appear as little 

 shoots in its chinks, soon developing leaves and stems as a 

 'separate plant.'— Dr. Habley also gives good ground for believing 

 the perpendicular roots penetrate the hard wood by their own 

 growth, in the absorption they occasion in the wood itself, and 



