110 MISSOURI BOTANICAL GARDEN. 



rice. They vary in color from dark green to dark brown. 

 As they grow older they become rather hard and dense, 

 but bear no definite fruiting bodies. 



Perithecia. 



In all of our cultures no perfect form of fruiting has 

 been found, although the fungus has been grown on all the 

 common culture media. If such form exists, our failure 

 to find it is due to the fact that natural conditions were 

 not imitated closely enough to produce it. 



The Formation of Color. 



On pine sap wood, a red or purple color is produced, 

 which in old cultures fades to a dirty brown. A number 

 of species of Ftisariwn are now being grown on pine wood 

 for comparison with this, and the results will be published 

 at a later date. Fiisarium roseum secretes a soluble pig- 

 ment which is taken up by the adjacent wood cells, stain- 

 ing them lightly with a red or purple color, which varies 

 with the acidity or alkalinity of the wood. In natural 

 wood, which is slightly acid, the color varies from a pink 

 to a lilac. In cultures where there is a profuse growth of 

 the mycelium the colored chlamydospores and mj'celium 

 modify the appearance of the wood, giving it a dull color 

 in contrast with the original brighter one. 



CAUSES OF COLOR IN WOOD STAINED BY THE FUNGI 



INVESTIGATED. 



1. Ceratostomella. 



The cause of the blue-gray or blue-black stain in wood 

 penetrated by the mycelium of Ceratostomella lies in the 

 color of the filaments of the fungus, which exudes no stain 

 from its mycelium. The dark brown pigment in the walls 



