228 



Cave, Ky. Mammoth Care, as well as can be told by scaling on tbe map, is 

 approximately 215 miles from Lafayette. It is conceivable, of course, that 

 ;i wind-borne spore from such a Peridcrmium could have started the in- 

 fection of Silphium plants each year : but when we consider the likelihood 

 that the two species do not belong together, and the fact that the rust was 

 found in practically the same place both times, together with the fact that 

 the host is a perennial plant, it seems more reasonable to think that the 

 original infection was started by a stray spore, and that its further propaga- 

 tion and carrying over the winters was accomplished in the uredinial stage, 

 either by surviving spores, or by mycelium in the living host. 



A somewhat similar case is that of Goleosporium Ipomoece, which has 

 been collected repeatedly in Tippecanoe County since 1895 on Ipomoea 

 pandvrala. It occurs in great abundance and is doubtless to be found in 

 practically all parts of the State where this host is found. The same thing 

 is true for this species as for the preceding regarding the alternate stage 

 and the possibility of the epidemics being started by a^ciospores, with this 

 addition, that because of the more general distribution and greater common- 

 mess of the fungus, it is much less likely to be started each year by 

 reciospores. 



Goleosporium Vernonue, on different species of Vernonia, has for its 

 secial stage Peridermmm carneum on Pimis Elliottii and P. palustris. It has 

 a very wide distribution in the State, being represented in the Arthur 

 herbarium from eight counties. The hosts of the secia according to Sud- 

 worth 30 and Small 37 are both confined to an area south and east of central 

 North Carolina and the north third of Alabama. This distance from 

 Lafayette, as scaled on the map, is approximately 430 miles, a distance 

 about 2.5 times as large as our maximum distance which we might expect a 

 rust to migrate in a season. Moreover, it has been collected at Lafayette 

 in different years as early as July IS and July 24, which dates are early 

 enough in the season to render it even more unlikely that the infections 

 were developed, even indirectly, from seciospores of the same season. 



Goleosporium Campanula is a species occurring in Indiana on Campa- 

 nula amcricana. The reciuin is known as Peridermium Rostrupi and occurs 

 on Pinus rigida in eastern Ohio. The closest approach of the range of the 

 host to Lafayette, according to Sudworth's map 33 is in eastern Ohio, which is 



"1. c. Map 35. 



37 Flora of the Southeastern United States 33. 1913. 



"Forest Atlas. Geographic distribution of Xorth American Pines. Parti. Map 26. 1913. 



