UROMYCES 



295 



of which often remain in the dead leaves until the following 

 spring, when they germinate and infect any of the host- 

 plants within reach. 



Uromyces betae is very common on wild beet (Beta 

 maritima), which is the origin of sugar beet, beetroot, and 

 mangold, and the fungus common on the wild beet has 

 passed on to the various cultivated forms. In addition to 

 this, these cultivated forms, now growing in countries where 

 the wild beet does not exist, are as badly infected with 



^ , 



FIG. 86. Uromyces betae. i, portion of a mangold leaf dis- 

 eased ; 2, portion of leaf with a cluster of aecidia ; 3, section of 

 portion of leaf with two uredospore pustules ; 4, aecidiospores ; 5, 

 uredospores ; 6, teleutospores. Fig. i reduced, remainder mag. 



Uromyces betae as are our European plants. This I consider 

 as one of the proofs that the fungus is by some means carried 

 along with the plants to new countries. Now as beet or 

 mangold is only introduced to new countries by means of 

 seed, it follows that fungus spores must necessarily have been 

 conveyed along with the seed. The disease has already been 

 recorded from S. Africa, Australia, New Zealand, and the 

 United States. 



* The spermogonia are yellowish in colour and arranged in 

 small, inconspicuous groups. Aecidia whitish with an 

 irregularly fringed margin, small, arranged in circular groups 

 on yellowish patches ; aecidiospores globose or broadly 



