87 



interstices and contacts were gray, the borders olive; in the old regions 

 the interstices were dark, contacts gray, and borders deep black. No 

 sclerotia developed. 



H. No. 2 gave quite distinctive color-characters, as did also Nos. 11, 

 12, 16, 17, and 19, including the colors pink, brown, red, gray, and purple. 

 The remaining strains were distinguished only by sclerotial development, 

 in which character strains known to be closely related differed markedly. 



Additional notes made on these cultures at later periods, up to four 

 weeks, differed only as to sclerotial development and the wasting away 

 of the rice column. At four weeks H. No. 1 produced some sclerotia, and 

 at five weeks, many. 



In an attempt to ascertain wherein lay the responsibility for the 

 various colors found in rice cultures, tubes w r ere made in the usual way, 

 using rice chaff, whole rice, rice from the pearling cone, rice from the 

 brush, and rice polish. Of these, rice chaff and whole rice gave no color 

 reactions; but all the others gave the usual ones. Single grains of auto- 

 claved rice w r ere placed on washed agar, under a cover-glass, and inoculated 

 with color-producing Helminthosporiums. Direct microscopic observa- 

 tion showed the most intense colors on the unbroken rice-surface, and less 

 intense ones on interior regions exposed by breaking. It is therefore 

 probable that the proteids, which are most abundant in the surface layers, 

 are necessary to the color responses, though the color itself often, if not 

 always, arises from the mycelium. 



Pearl-barley (prepared like rice tubes], The general character of 

 the growth as to contacts, interstices, and borders was as on rice but 

 w T ith different and less pronounced coloring. H. No. 1 at two weeks gave, 

 in the recent region, salmon interstices, contacts, and borders; in the 

 median region, gray interstices and contacts and olive borders; in old 

 regions, dark interstices, gray contacts, and black borders; and the aerial 

 mycelium was gray and the barley column not shrunken. 



Navy beans (prepared like rice tubes). H. No. 1 grown on this medium 

 two weeks gave contacts unchanged, interstices gray to brown, borders 

 brown to black. Little of differential value developed, though H. Nos. 11 

 and 19 gave pink colors. 



Wheat grains (prepared as above). H. No. 1 in old region gave con- 

 tacts unchanged, interstices dark gray, borders black, and a very few 

 sclerotia developed. H. No. 3 gave the same characters but more numer- 

 ous sclerotia. 



