440 



FUNGOUS DISEASES OF PLANTS 



II. GALL OF HEATHS 

 Exobasidium Vaccinii (Fckl.) Wor. 



RICHARDS, H. M. Notes on Cultures of Exobasidium Andromedae and of 

 Exobasidium Vaccinii. Botan. Gaz. 21 : 101-108. pi. 6. 1896. 



SHEAR, C. L. Cranberry Diseases. Bur. Plant Ind., U. S. Dept. Agl. Built. 

 110: 35-37- pi- 7- i97- 



Relationship of forms. Much cross-inoculation work is needed 

 to determine the relationship between forms of Exobasidium on 

 different species of heath (Ericaceae). These fungi are found 



upon certain more or less 

 closely related hosts, generally 

 in bog-like habitats throughout 

 considerable portions of Europe 

 and North America. 



The fungus upon Vaccinium 

 Vitis-idaa is considered the 

 typical form of the species 

 here discussed. Upon the host 

 referred to, pale rose or red- 

 dish, thickened spots are pro- 

 duced. The same species 

 occurs, apparently, on other 

 species of Vaccinium, also 

 Gaylussacia and other genera, 

 and it may be well briefly 

 to refer to some of its related forms. No morphological char- 

 acters of the fungus above mentioned have been found which 

 would distinguish it from Exobasidium Oxycocci Rostr. on the 

 cranberry (Vaccinium macrocarpon). On the cranberry, however, 

 lateral buds are attacked, and as these exfoliate, a considerable 

 portion of the shoot may become hypertrophied. The affected 

 leaves are rose colored, and since they remain close together on 

 the shoot, they are often called false blossoms. A form produc- 

 ing characteristic galls on the young shoots of several species of 

 rhododendron is generally regarded as distinct, and bears the 

 name Exobasidium Azalea. Finally, there is an unusually large 

 form described as Exobasidium Andromeda Pk., which produces 



FIG. 215. EXOBASIDIUM VACCINII ON 

 RHODODENDRON 



