Jan. 14. 1918 Cultures of Wood-Rotting Fungi on Artificial Media 47 



DISCUSSION OF CUIvTURAI^ TABIvES 



Fames texanus. The cultural characters for all of the four strains 

 show remarkable uniformity for each of the corresponding agars in the 

 series of ten. This fungus seems to be more susceptible to differences 

 in the amount of sunlight it received than any species thus far inves- 

 tigated. When the intensity of the sunlight was diminished by the 

 cheesecloth screens previously mentioned, this species on several of the 

 agars immediately responded to the decrease in Ught by making a more 

 vigorous growth and turning a lighter shade of brown. 



Polyporus jarlowii. This fungus is also very uniform in growth on 

 each of the 10 agars as the tables show. When grown in the dark, the 

 strain from Acer negundo developed a submerged mycelium on prune 

 and corn-meal agars which was Mars brown in place of colorless. Whether 

 this change in colors of the mycelium was due to the darkness is doubtful 

 since the other strain from Populus iialica when grown in darkness still 

 retained its colorless mycelium the same as when grown in the light. 



Series were grown of nine strains of Trametes pini obtained from 

 material collected in four States and growing on seven hosts — ^viz, Pinus 

 echinata, P. fiexilis, P. ponderosa, Picea engelmannii, Pseudotstiga taxi- 

 folia, Abies arizonica, and A. lasiocarpa. This series represented sub- 

 cultures ranging from i to 7. While there was some slight variation, 

 especially in the colors of the mycelium of the various strains, the dif- 

 ferences were not so marked as to constitute real specific characters. 

 There was practically no difference between the cultural characters 

 obtained from the different subcultures. This would indicate that the 

 general fundamental characters of the fungus are not materially changed 

 through successive subcultures, at least in this instance to the seventh 

 subculture. 



As will be noted from the temperature record, there was rather a wide 

 variation in temperature during the time the various series of cultures 

 were growing. Nevertheless the general cultural characters as shown in 

 tables are practically identical. This identity of characters for a given 

 organism on a given culture medium is still more marked when a series 

 of from three to six tubes of the same agar for the same strain is made 

 at the same time and then compared as the growth progresses. 



CULTURAL CHARACTERS FOR DIFFERENT STRAINS OF SAME FUNGUS 



The sources of the initial cultures from the nine strains of Trametes 

 pini were five from sporophore tissue and four from infected wood, rep- 

 resenting seven hosts, while the cultures from Fomes texanus all were 

 from tissue but from two hosts. The Polyporus farlowii cultures were 

 both from tissue but from different hosts. A careful comparison of the 

 cultural characters of the various strains of each of these fungi shows 

 no appreciable differences between cultures of a given fungus whether 

 obtained from infected wood or from sporophores; neither do the hosts 



