40 Journal of Agricultural Research voi. xii, no. 2 



any great length of time. The long, divergent, aerial strands usually 

 become more or less compact and finally felty. The usual steps in the 

 growth of the mycelium of a fungus are first appressed, then downy, 

 then felty, woolly, etc. Cottony mycelium usually develops the cottony 

 stage immediately from the appressed condition. Many of the fungi 

 pass so rapidly from the downy to the felty or woolly stage that it is 

 unnecessary in the description to indicate that there is an intermediate 

 downy stage. 



Colors. — The colors of the fungus as a rule follow certain definite 

 changes. Excluding the color of the mycelium on the inoculum, the 

 first color which usually appears in the early stages of the fungus will 

 be either colorless or white, depending to a considerable extent on 

 whether the young mycelium is appressed or downy. The next step in 

 the color changes will be for the older whitish areas to become light 

 buff \ warm buff, antimony yellow, etc., if the fungus happens to belong 

 to some of the brown polyporaceae. As the culture ages, the color of 

 the mycelium on the older areas will assume a deeper and deeper tone 

 until finally a color is reached beyond which no appreciable change is 

 observed. In the large majority of cases the color of the older mycelium 

 constitutes a rather extended area compared to that of the 5^ounger 

 zone. In practically every instance the cultures obtained from any 

 given fungus on at least several of the culture media will approach very 

 closely the color of the sporophores as they appear in nature. For 

 instance, if one is attempting to grow cultures of Polyporus dryophilus , 

 Fomes texanus, or other brown fungi, one would expect to have at least 

 several of the culture tubes with brown mycelium similar to that of the 

 fungus. 



TABLES SHOWING CULTURAL CHARACTERS 



In this preliminary report only a few tables are given out of a large 

 number which the writers have complied on the cultural characters 

 of certain species of wood-rotting fungi. The following species having 

 brown sporophores are given to illustrate the close resemblance in colors, 

 texture, etc., of the same fungus on different hosts: Four strains of 

 Fomes texanus (Tables I-IV) and two strains of Polyporus farlowii 

 (Tables V-VI). 



' The colors used in this paper are according to the following standards: 



RiDGWAY, Robert, color standards and color nomenclature. 43 p., 53 col. pi. Washington, 

 D.C. 1912. 



