370 UREDINEAE. 



M. ariae (Sehleich.). On leaves of Pyrus aria. 



M. padi (Kunze et Schum.). On leaves of Prunus Padus. (Britain.) 



M. hypericonim (D.C.). On Hypericum. (Britain.) 



M. pustulata (Pers.). On EpUohium. (Britain and U.S. America.) 



M. circaeae (Schum.). On Circaea. (Britain.) 



M. vaccinii (Alb. et Sclim.) On leaves of Yaecinium. (Britain and U.S. 

 America.) 



M. pirolae (Gmel.) On Pyrola. (Britain and U.S. America.) 



M. sparsa Wint. (U.S. America). On Arctoataphyhs alpina (also A. 

 officinalis ace. to Bostrup). 



M. carpini (Nees.). On leaves of hornbeam. 



M. galii (Lk.). On Galium. 



M. (Thecopsora) agrimoniae (D.C.) On Agrimonia. 



M. vemalis Niessl. Teleutospores only on Saxifraga granvlata. 



M. helioscopiae (Pers.). On Euphorbia. (Britain.) 



M. euphorbiae-dulcis Otth. 



Melampsorella. 



The unicellular teleutospores are developed in the cells of 

 the epidermis and form reddish patches. The patches of 

 uredospores are enclosed in a peridium. 



Melampsorella cerastii (Pers.). Uredo- and teleutospores on species of 

 Stdlaria and Cerastium. (Britain and U.S. America.) 



Calyptospora. 



The teleutospores are developed inside the epidermal cells, 

 and are divided into four cells by vertical septa. The aecidia 

 have large peridia. The pycnidia are small and precede the 

 aecidia. 



Calyptospora Goeppertiana Kithn.^ (U.S. America). The 

 common disease of cowberry {Vaccinium Vitis-Idaea) caused by 

 this parasite is shown externally by a very marked swelling 

 and elongation of the shoots (Fig. 202). Diseased plants 

 elongate conspicuously above their neighbours, and in this way 

 distribution of their spores by wind is facilitated. The mycelium 

 hibernates in the cortical tissues, and maintains itself for years. 

 It grows intercellularly, sending haustoria into the cortical cells. 

 As a result of its presence, cell-growth is much accelerated, 

 and a marked thickening of attacked twigs frequently occurs ; 



'R. Hartig, Lehrhuch d. Baumkrankheiten , i. Aufl. p. 56 and PI. II. (The 

 2nd edition and the English translation are somewhat abridged.) 



