112 Mycologia 



hosts, with degree of maturity and somewhat with environmental 

 conditions. Racial differences are well known. The uredinia of 

 stem rust have been studied; and dates kept of the earliest and 

 latest appearance, but a discussion of this stage will be left for 

 the future. 



As compared to the uredinia, the telia of stem rust of the 

 cereals are rare and underdeveloped in this state. At harvesting 

 time, or indeed at any other time, while the uredinia may be 

 readily found it usually takes careful searching to obtain telia. 

 Moreover, examination of telia under the microscope shows 

 spores which are considerably undersized and otherwise abnor- 

 mal. In the fall of 1918, as well as in the fall of 1919, wheat 

 straw containing telia, collected around Fayetteville, were put 

 into wire cages and allowed to remain out of doors during the 

 winter. No germination occurred, in contrast to the teliospores 

 of over-wintered material of Elymus australis which germinated 

 profusely as will be described. No explanation is at hand for 

 this lack of normal telial development. It seems probable that 

 the frequent and prolonged " dry spells " characteristic of the 

 growing seasons of this section may have some influence on the 

 development of telia. Possibly the time of wheat harvesting, 

 usually in the first half of June, coming considerably earlier than 

 in the sections where a profuse development of normal telia is 

 common, as in the spring wheat section, may have something to 

 do with it. 



But while the cereal grasses ordinarily do not produce viable 

 telial material the writer has carefully checked up the viability 

 and infectivity of this stage on Elymus australis, 1 one of the com- 

 mon grasses of the region around Fayetteville. It is rather 

 drought resistant, frequently to be seen making good growth 

 when other grasses, both wild and cultivated, are either dead or 

 suffering for want of moisture. During the fall of 1919 a very 

 heavy infestation of the stem rust, in the form of telia, was noted 

 in a good-sized patch of Elymus growing along a road side. The 

 telia, unlike those observed on the cultivated cereals, appeared 

 well developed, of a blackish color, and when examined under 



1 The writer is indebted to Mrs. Agnes Chase of the U. S. Department of 

 Agriculture for the identification of this grass. 



