DISEASES OF TAXODIUM AND LIBOCEDRUS. 



a distinct mycelium is present, and the probabilities are 

 strong that it is the one which brings about the decay of 

 the wood. The hyphae are brownish when young, but 

 soon become colorless . Their chief and striking characteristic 

 is the presence of very many clamp connections (PL 5, fig. 

 1). Brefeld,* Hartig,f and others have shown that these 

 organs are to be found among the Basidiomycetes, particu- 

 larly among the Agaricineae and Polyporei. Brefeld (I.e.) 

 describes their formation in Coprinus stercorarius as lateral 

 outgrowths of one cell fusing with the cell beneath it, and 

 then forming a separating wall. At such points numerous 

 branches usually appeared. Hartig (1. c.) describes the 

 clamp connections of Merulius lachrymans. In this fungus 

 they bud out, and form a branch, sometimes before the 

 separating wall in the clamp has fused with the next cell. 

 This is a unique case among the Hymenomycetes, as the 

 clamps are " sterile " in all other forms. 



The clamp connections occur on all parts of the mycelium 

 found in Taxodium, but in no case did any of them branch 

 as they do in Merulius. The mycelium consists of large 

 hyphae with distinct thin walls, and hyphae of smaller diame- 

 ter. The larger hyphae are constricted at the points where 

 two cells join. They branch frequently, giving rise to the 

 hyphae of smaller diameter. These in turn branch and 

 rebranch. At certain points a short branch is given off. 

 which divides very rapidly into the finest threads, of hair- 

 like dimensions. These smaller hyphae penetrate the cell- 

 walls in all directions. Connections between adjacent 

 hyphae occur frequently, also complicated masses, where 

 large numbers of hyphae have fused more or less. As a 

 rule there is but very little mycelium to be found either 

 in the much rotted wood or the intermediate parts. Nu- 

 merous holes occur all through the wood, indicating where 



* Brefeld, O. Untersuchungen iiber Schimmelpilze 3 : 16. 1877. 

 f Hartig, R. Der achte Hausschwamm 14. pi. l,fig. 3. 



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