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is also the active g:rowing .season Idr tlio Imst plants. Any sort of spores 

 cau be employed for the experiments and the methods vary accordingly. 

 A smaller portion of the work, with urediniospores and tellospores which 

 germinate at once, may be carried on through ihe summer months and 

 early autumn. 



The best success has been attained through tlie sowing of teliospores 

 which give rise to pycnia and aecia in turn. All grass and sedge rusts 

 furnish telial material, and since they are, with a single exception, known 

 to be heteroecious, any collection affords culture material. Teliospores 

 are usually resting spores and normally retain their viability tlirough the 

 winter. Collections made in the fall and kept in a warm, dry room 

 during the winter usually fail to germinate. The freezing temperature of 

 the outdoor atmosphere does not seem to l)e detrimental, and some plan 

 to prevent the specimens from thoroughly drying is a necessity. Cloth 

 packets are to be preferred to paper, as they do not take up moisture so 

 rapidly and allow a better circulation of air. These packets may be 

 hung out of doors, or an unheated shed without a floor seems to furnish 

 good conditions. The material put up in this manner may be sprayed 

 occasionally in the fall and winter, but an effort mu^>t l)e made to keep 

 them in a uniform condition. Collections made in the early spring after 

 they have wintered over in the field usually show vigorous germination. 

 Late spring collections arc of less value, as the most vigorous are liable 

 to have grown in the field. Spores collected as early as July and August 

 have beeu brought to germination and have been sown with success, 

 but October and November collections survive through the winter better. 

 In the spring the packets are brought into a warm room some little time 

 before conditions outside are favorable for growth, and after a few days 

 of warmth and moisture some of the spores will show signs of growth. 

 The packets may be sprayed and thrown together in heaps, but they must 

 l)e spread out and aired and caution taken to prevent molds from 

 starting. The material in germinating comlition is carefully separated 

 from that not yet ready to germinate. 



If negative results are to be given ;uiy weight the spon^s must be 

 tested just before a sowing is made to ascertain if they arc in ger- 

 minating condition. Teliospores of Pucciniaceous species are tested by 

 means of a hanging drop culture. In a space of twenty-four hours viable 

 spores push out germinating tubes which are readily made out with the 



