10 0. S. U. Naturalist. [Nov. 



stunted growth. The new stalks that appear now and then are in- 

 variably atfected, though sometimes one of the panicles, either tlie 

 one terminating the main stem or one of the side branches may be 

 free from visible smut. It is thus evident that tliis species of smut 

 is perennial where its host lives from year to year. Figure 3 shows 

 a photograph of one of the plants started in the greenhouse in 1899, 

 its first stem producing an infected panicle. Figure 4 shows a plant 

 grown in 1900, the first or central panicle not exliibiting the smur, 

 but later when panicles from the side branches appeared, they were 

 seen to be smutted. 



It seems that another experimenter, whom I will quote, has 

 succeeded scarcely as well. Mr. G. P. Clinton, the assistant Botanist 

 of the Illinois Experiment Station, Urbana, Illinois, in Bulletin No^ 

 57 (March, 11)00) reports as follows: "Apparently from the experi- 

 ments of Kellerman, infection takes place through the germinating 

 seed, though the percent, of infection he produced was rather small. 

 In '98 field experiments were conducted herewith a view of infect- 

 ing the Orange variety of sorghum with this smut. In one case the 

 seed was mixed with an abundance of spores and|in others these 

 spores were sprayed ia water or manure water on the young parts of 

 the plants when about six inches high. In none of the several hun- 

 dred plants that matured was any sign of the smut found. It is very 

 likely that the variety used may have had something to do with the 

 negative results, as it was not the same from which the smut was 

 taken." 



The head-smut of sorghum is not to be confused with another 

 species tliat occurs on the same host. The one now referred to is a 

 grain-smut, that is, the panicle as a whole is not included, but the 

 individual grains become smutted. This species has been called 

 UstUago sorghi, but Mr. Clinton regards it as a Cintractia, namely, 

 Cmtractia sorghi-vulgaris (Tul.) Clint. It is more common than the 

 former, occurring often on sorghum and broom corn. 



The head-smut of sorghum, Usdlago or Ciniraciia reiliana, 

 was first found in this country by Prof. J. T. Willard at Manhattan, 

 Kansas, in 1890, in a plot grown for purposes of chemical investiga- 

 tion. The same year it was detected by Dr. Halsted in New Jersey. 

 I found it in Ohio in 1897 and it is now reported for Illinois by Mr. 

 Clinton. In all these cases it occurred only on sorghum, but Prof. 

 Hitchcock has reported it as not uncommon on maize in fields about 

 Manhattan, Kansas. 



Exi'LANATiON OF PLATE 2. — Ustilago Or Ciiitractia reiliaiia. Figure 1 ; Tlie foliicolous form 

 occurring on sweet corn, the panicle not yet emerged, hut tne smut on upper leaves iu sight. 

 Figure 2: Same as in Figure 1, showing a later stage of maturity. Figure 3: An infected 

 sorghum plant in the greenhouse, photographed in 18!t9, the panicle smutted. Figure 4 : An 

 infected sorghum plant, grown in the greenhouse in I'JUO, the central panicle sound, the later 

 (side) panicles smutted. 



