114 MISSOURI BOTANICAL GARDEN 



darker line at the edge of the heart wood, while the sap 

 wood itself is darkened where it is apparently taking on 

 the characteristics of heart wood prematurely. A tree 

 which has a sporophore upon it is always more or less 

 seriously affected and the rot extends from a few inches to 

 as many feet longitudinally in the tree. 



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seem to have any single component extracted to any very 

 serious extent. In the last stages of the disease, however, 

 there are quite extensive streaks and patches of cells in the 

 spring wood which have been so affected that their wall; 

 give the cellulose reaction. These areas are always 

 located in the early wood of the annual rings, but the late 

 wood still retains its normal yellow color. On testiuo- the 

 wood it was found that the white portions turned blue 



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arate from each other. The wood fibres are seen lying 

 loosely beside each other and stained blue with chlor-iodide 

 of zinc. The starch, which is commonly so plentiful in the 

 medullary rays, is wholly absent in the whitened tissues. 

 In the earlier stages of the rot scattering medullary ray 

 cells are found containing considerable quantities of starch. 

 These starch grains took the blue color and seemed to be 

 rather smaller than normal. In medullary ray cells of 

 medium stages of the disease a quite definite layer is seen 

 lining the cell and not taking the stains for lignin and also 

 not taking the stain for cellulose. Tests made upon the 

 white tissues of the early wood of the annual rings seemed 

 to show that the lignin was wholly extracted. Maule's 

 potassium permanganate test gave a bright red only in the 

 unaffected tissues. This was true also with phloroglucin 

 and other lignin tests, while chlor-iodide of zinc gave the 





blue reaction in the white and worst affected tissues. As 

 mentioned above, the middle lamellae were dissolved wher- 

 ever the lignin was extracted from the walls. 





