CHROMOGENIC FUNGI WHICH DISCOLOR WOOD. 77 



almost black, color. The development of the fungus on 

 wood is slower than that of C. pilifera^ staining pine, oak, 

 elm and ash with a blue-black discoloration contrasting 

 sharply with the unstained portions. The mycelium pen- 

 etrates pine wood through the medullary rays, and in some 

 cases enters the wood fibres. The hyphae of the hyaline 

 mycelium bearing conidia average 2.5/t in diameter, while 

 the dark brown filaments in wood measure from 2/* to 

 6/x, averaging 4/t in diameter. On the surface of wood 

 in the vicinity of perithecia some filaments have swollen 

 cells. Many of the filaments in wood cells have fine trans- 

 parent roughenings all over the surface. 



Conidia. 



The conidia, like those of C. pilifera, are borne in 

 whorls of single spores and short moniliform chains inter- 

 mingled (pi. 6, f. 4, 5). In older cultures they drop 

 together in clusters resembling somewhat those of Cepha- 

 losporium. They are oval to elliptical in shape, one-celled, 

 hyaline, and vary in size from 3.5/x to 4.5/t, in length, and 

 1.6/* to 2.2/* in width, averaging 4//. by 2/t (pi. 6, f. 6). 



Perithecia. 



In artificial as well as in natural growths, the perithecia 

 are very abundant. They are formed in large numbers 

 under favorable conditions after 10 to 14 days. The pro- 

 cess of formation is similar to that of O. pilifera. The 

 perithecia are globose. They are black, brittle, with a 

 roughened surface. They measure 60/* to 80/*, averag- 

 ing 73//. in diameter, with a beaked ostiolum 150/4 to 200/* 

 in length, and 8/* to 18/* in diameter, averaging 180/* by 

 14/* (pi. 3, f. 2). The asci are hyaline, irregularly 

 oval to elliptical, and contain 8 spores, often arranged in 

 fours. The ascospores are hyaline, elliptical, sometimes 

 slightly curved, and measure 2.1/* to 2. 8/t in length, and 

 .8/t to l.l/i in width, averaging 2.5/* by 1/* (pi. 6, f. 7). 

 T'.ie sacs usually disappear before the spores are ejected. 



