242 Proceedings of Indiana Academy of Science 



the spores. This has been found to be especially true in the case of the 

 aecia of the leafrust of wild grasses, Puccinia Clematidis. If the latter 

 are gathered when thoroughly mature, they can be sent long distances, 

 drying out on the way, and satisfactory cultures may be obtained in 

 most cases. Aeciospores of Puccinia Inipatientis have been dried rapidly 

 for two days in a plant press heated to a temperature of 27° C, and 

 excellent germination obtained from them. Aeciospores of this same 

 species also have given good germination after dry storage in a packet 

 at room temperature for 25 days. Aeciospores of Puccinia triticina, 

 similarly kept, gave excellent germination at the end of 5 days, a slight 

 percentage of germination still being obtained at the end of 28 days. 



Uredinial material of Puccinia triticina has been sent by mail from 

 many points over the United States and no difficulty has been experi- 

 enced in obtaining good cultures. Wheat leaves infected with this rust 

 were collected in 1923 at Hanford, Calif., on -June 7; Knoxville, Tenn., 

 June 12; Washington, D. C, June 16; Harmony, Wash., June 21; Ur- 

 bana, 111., June 27; Bloomington, 111., July 5; Wanatah, Ind., July 9; 

 Madison, Wis., July 23; and St. Paul, Minn., on July 24, and mailed to 

 Lafayette, Ind., as described above. They wei-e kept in an ice-box at 

 approximately 9 to 12° C, until Nov. 13, when sowings were made from 

 them on wheat, a fair amount of infection being obtained in each case. 

 In other words, urediniospores of Puccinia triticina, 159 days after col- 

 lection, were .still able to give infection. 



On Jan. 26, 1921, ui^ediniospores of Puccinia Sorghi and Puccinia 

 tnticina were collected from greenhouse material and distributed in 

 small cotton-stoppered vials at temperatures of 10, 15, 20, 25, 30 and 

 35° C, and outdoors. The germination of these was determined at 

 various times until March 1. Both rusts showed a gradual reduction 

 in germination after storage at the higher temperature, 35, 30, 25° C. 

 About the same or slightly less germination was maintained at 20, 15, 

 10° C, while spores stored outdoors showed even better germination on 

 March 1, when last examined. Peltier (1922) has investigated this 

 question extensively for Puccinia graminis. Fromme (1913), Melhus 

 and Durrell (1919), Peltier (1922), and Doran (1922) give data ob- 

 tained by themselves and other investigators .showing that the ger- 

 minability of aeciospores and urediniospores of a number of species of 

 rusts may be retained from 30 to 112 days. In general, germinability 

 is retained longest at lower temperatures. Storing these spores dry at 

 the cool temperature and moderate humidity of a refrigerator, either 

 on the dry host or in vials, may be a useful method of carrying rusts 

 over the summer, when it is not desirable or impossible to carry on in- 

 vestigations because of high greenhouse temperatures. 



Teliospores may be collected and mailed in a similar manner. As 

 in many species the.se are resting spores, the usual difficulty is not to 

 prevent loss of viability but to bring about germination. The viability 

 of the teliospores of those species which germinate at once may be pro- 

 longed, however, by refrigeration. Those which usually germinate only 

 after overwintering are hung out of doors in cheesecloth bags within 

 a foot or so of the ground. In this way, they are brought into a ger- 



