DISEASES OF TAXODIUM AND LIBOCEDRUS. 



would place it with the tannins. Hartig found tannin 

 in decayed wood, whereas it was not present in sound 

 wood, and in the present case there seems to be a similar 

 instance. What the origin of the tannin may be I do not 

 venture to say. 



Aside from the tannin a brown humus compound, similar 

 to that found in Taxodium, occurs. It is found in the 

 form of irregular granular masses which readily dis- 

 solve in dilute KOH. The medullary rays in particular 

 are filled with this substance (PI. 4, fig. 2); it seems 

 to permeate the cell- walls, for these turn the characteristic 

 yellowish-brown color on addition of KOH, and the tra- 

 cheids become filled with the brown liquid. Extractions of 

 the surrounding wood with KOH yield considerable quan- 

 tities of the compound. Nowhere were any dried plates 

 found, such as were described for the cypress. 



MYCELIUM AND SPORES. 



The mycelium found in the diseased Libocedrus wood 

 agrees so closely in appearance with that found in the 

 Taxodium that the drawing on PI. 5, fig. 1 may represent 

 it as well. Few hyphae are to be found in the charred 

 wood or the wood about the holes. Abundant evidence of 

 their having been present is seen in the numerous holes 

 which puncture the walls of the charred wood in all direc- 

 tions (PI. 4, fig. 2). No preference is shown for the 

 pits. The hyphae are most abundant in wood away from 

 the rotted holes. They are colorless, branch frequently 

 and are provided with a large number of clamp connec- 

 tions. The finest threads pass through the walls in all 

 directions. Between the rotted areas the hyphae usually 

 extend directly from hole to hole, just as in the Taxodium. 

 In places the mycelium collects in large masses or felts ; in 

 these felts the hyphae are matted. Many crystals of 

 calcium oxalate give the whole a white appearance. 



A brown mycelium like that found in the cypress was 



51 



