4 Robert S. Kirby 



Hordeum, Hystrix, Phleum, and Stipa — became affected. Of all the 

 genera tested, the fewest resistant species were found in Agropyron, Elyinus, 

 Hordeum, Hystrix, Stipa, and Triticum. Of these, the species in Triticum 

 seem to be the most susceptible since they are the only hosts to show any 

 marked degree of hypoplasia. 



RELATIVE SUSCEPTIBILITY OF GRASSES AND OF CEREALS 



Grasses 



The most important role of the grass hosts, excluding the cereals, is 

 as harborers of the pathogene. Since the importance of the individual 

 host in this respect depends upon the number of perithecia produced on it, 

 the evidence presented in table 1 is given in terms of the relative number 

 of perithecia. The number of perithecia was determined for each species 

 by dissecting numerous culms under the binocular. On all grasses reported 

 as hosts, typical perithecia and ascospores have been found. 



The host-range tests made in the greenhouse and tabulated in table 1 

 represent a repetition and extension of those previously reported by the 



TABLE 1. Host Range of Ophiobolus cariceti as Observed jfrom Inoculation Tests in 

 the Greenhouse, Observations in the Field, and Reports of Other Investigators 



* All the grasses in this test were grown from seed obtained from the following sources. Dr. E. B. 

 Mains, Purdue University, LaFayette, Indiana; Professor A. H. Larson, Seed Laboratory, University of 

 Minnesota, St. Paul, Minnesota; Berkeley, California, grass gardens of the Cereal Office of the United 

 States Department of Agriculture. 



f Few=less than ten perithecia per culm. 



Moderate=from ten to forty perithecia per culm. 

 Many=more than forty perithecia per culm. 

 t References to literature in last column: 

 l=Saccardo (1875) 

 2=Waters (1920a) 

 3=Brittlebank (1920) 

 4=Berkeley and Broome (1861) 

 5=Anonymous (1919) 

 6=McAlpine (1904) 

 7=Rosen and Elliott (1923) 

 8=Anonymous (1907) 

 9=Hori (1901) 

 10=Peglion (1898) 

 ll=Stakman (1922) 

 12=Pridham (1919) 

 13=Anonymous (1922a) 

 14=Kirby (1922) 



