Red Wood in Conifers. 



113 



On 10th August, 1907, some of these plants were examined. 

 Very conspicuous layers of red wood were developed on the under 

 surface of both parts of the curve, just as described in the 

 " Annals of Botany."' Sections were cut from the parts of the 

 curve where the development of red wood was greatest, and the 

 internal diameters of the red and white tracheides, and also the 

 thickness of their walls, were measured. 



Experimental Results. 

 Pinus strobus. 



Sectiox I. — (From upper purtion of curve). 



Red Wood White Wood 



Iiittiiial Diameter Thickness of Wall Internal Diameter Thifkiiess of Wall 



.008 mm. .003 mm. .012 mm. .006 mm. 



.010 ., .002 ,, .012 ,, .006 ,, 



.009 ,, .003 ,, .010 ,, .006 „ 



.010 ,, .002 ,, .010 ,, .007 ,, 



Average Average Average Average 



.009 mm. .003 mm. .011 mm. .006 mm. 



Section III. 

 Red Wood White Wood 



Internal Diameter Thickness of Wall Internal Diameter Thickness of Wall 



.009 mm. .002 mm. 



.013 ,, 

 .008 ,, 



Average 



.009 mm. 



.003 ,, 

 .002 ,, 



Average 

 .002 mm. 



.008 mm. 



.010 „ 



.009 „ 



Average 



.009 mm. 



