COLEOSPORIUM. 



377 



occur on various species of Sonchus (without doubt on S, 

 arvensis). Aecidia are unknown. He relates it to Peridermium 

 Fischeri Kleb. on needles of Pinus sylvestris. 



0. synantherearum Fr. A provisional collective name for 

 aecidia on Adenostyles, Petasites, Gacalia, Senecio, etc., th^ life 

 history of which is as yet unknown. 



0. campanulae (Pers.) (Britain). TJredo- and teleutospores 

 on Campanulaceae {Campanula and Phyteuma). The aecidial 

 form is Peridermium Bostrupii on pine-needles. 



C. pulsatillae (Str.). Uredo- and teleutospores on Anemone 

 Pulsatilla and A. pratensis. Aecidia unknown. 



0. ipomoeae (Schwein). Uredo- and teleutospores on species 

 of cultivated Ipomoea in United States. Aecidia unknown. 



Fischer^ obtained pycnidia on needles of pine by infection 

 with a Coleosporium from Campanula Trachelium. 



Chrysomyxa. 



The teleutospores are formed closely together in yellow sori ; 

 each spore consists of an aoropetal series of cells, the distal 

 one of which, without leaving the sorus, germinates to produce 

 a promycelium of several cells. Uredospores are not always 

 present. The aecidia have well-developed peridia. 



Chrysomyxa rhododendri (D. C.).^ This is a common rust 

 on the Alps where the Alpine-rose {Bhudodendron feri'ugineum and 

 B. hirsutum) occurs. Immediately after the break-up of the 

 winter little dark-red cushions of this rust appear on the under- 

 side of the leaves. These contain the sori of teleutospores 

 already partially developed during the previous autumn, and 

 now, after hibernation, ready to increase in size and to rupture 

 the host-epidermis (Fig. 211). The teleutospores so exposed 

 germinate without leaving the sorus, and produce four-celled 

 promycelia, with sterigmata, from each of which a single 

 sporidium is abjointed. The sporidia make their escape in 

 June, and alighting on the unfolding needles of the spruce 

 {Ficea exeelsa), they germinate at once and produce Aecidixmi 

 ahietimim, the blister-rust of the spruce (Fig. 212). 



An intercellular mycelium is developed in the spruce-needles, 



''■ Botan. Centralblatt, Lix., 1894. 

 ^De Bary, Botan. Zeitung, 1879. 



