RUSTS l\ COLORADO 73 



understood to possess all spore forms in Its life-cycle, could 

 start out in early spring with telia followed by uredinia. 

 without a trace of pycnia or aecia. It appeared as if the 

 normal order of pycnia, aecia, uredinia and telia had been 

 reversed ; and it took some time to unravel the mystery. By 

 a number of small increments of observation the ultimate 

 conclusion was reached that the dried telia were the product 

 of the previous season's growth, and iji confirmation of 

 this, many wholly dried and shrivelled leaves were found 

 covered with telia. It was seen that the green leaves that 

 were found had remained green through the winter, and 

 kept the mycelium alive that gave rise to the fresh uredinia, 

 to be followed in the few instances where sufficient time 

 had elapsed by fresh telia. The adjoining old telia were 

 always on the dried tips, indicating that, like the old telia 

 on wholly dead leaves, they were the product of the previous 

 season. Finally a single collection was fortunately made of 

 pycnia and very young aecia, that must have freshly arisen 

 from telial infection derived from wintered spores. The 

 reason w^hy more aecia were not found was clearly due to 

 the lack of sufficient time for the wintered teliospores to 

 germinate, infect a new leaf, and secure development since 

 the beginning of spring; and the reason why abundant ure- 

 dinia were found was because their formation from existing 

 live mycelium in the persistent leaves required far fewer 

 days of warm atmosphere. This brings to light an interest- 

 ing instance of the wintering of mycelium, a method not 

 uncommon in grass and sedge rusts, but rather rare in other 

 herbaceous plants. * 



It was also in this cross-country trip that we were intro- 

 duced to the cedar rusts of Colorado, which constitute a 

 largely unworked portion of its fungous flora. In a narrow 

 gorge a few trees of Sabina scopuloriirn, the common red 

 cedar of the region, were pointed out by Mr. Bethel, on 

 which he had previously collected a bark rust. We found 



♦Cultures cnnfirnuMl tlir* inforcnii' drawn, see Jour. Myc. 14:23. 190S. 



