426 



BASIDIOMYCETES. 



cinium MyrtillvsY causing a premature fall of the leaf and 

 suppression of the flower. The external symptoms of the disease 

 differ somewhat from those on cowberry. Diseased leaves are 

 much larger than the normal, but are neither thickened nor 

 blistered ; on the under side they have a whitish or reddish 

 coating, and fall off easily. I have never observed the disease 

 on the stems of bilberry. In spite of these external differences, 

 it is believed that the host-plants are in both cases attacked by 

 the same species of Exobasidiuin, but I do not know of any 

 observations on the reciprocal infection of the two hosts. 



Fig. 259. — Bxohasidium rhododendn ou Rhododendron fen-ugineum. (v. Tubeuf phot.) 



A disease due to an Exdbasidium is by no means uncommon 

 on Vaccinium uliginosum (bog whortleberry).^ Shoots of diseased 

 plants are deformed, while their leaves become more or less 

 thickened and assume a beautiful rosy coloiir. 



On Vaccinium Oxycoccos (true cranberry) the shoots and 

 leaflets also become thickened and rose-coloured. Eostrup dis- 

 tinguishes this as a separate species {Exohasidium oxycocci). 



Ex. andromedae Peck, produces on Andromeda polifolia 

 symptoms similar to those just described for the preceding 

 species. (Britain and U.S. America.) 



' Sadebeok {Botan. Centrcdblatt, 1886) records it in large quantity near Harburg. 

 This is the host-species given by Massee (British Funtjus- Flora , 1892). 

 ^Tubeuf, " Mittheilungen." Zeitsch. f. Pflanzenkrankheiten , 1893. 



