380 UHEDIXEAK. 



formed, and in this condition the fungus hibernates, to develop 

 further in the following spring. It is only in very dry cold 

 winters that the needles dry up and fall off; as a rule they 

 remain on the trees. About the beginning of May the spore- 

 cushions break through the epidermis and give off multicellular 



teleutospores, which are as a rule branched. 

 Thence arise the four-celled promycelia, with 

 sterigmata, from which a single sporidium is 

 abjointed. 



Diseased needles- remain green except in 

 areas inhabited by mycelium ; yet needle- cast 

 soon follows liberation of the fungus-spores. 

 Starch is laid up in large quantity in diseased 

 FIG. 2i3.chrysomy.. : ,i needles during the first summer, but is com- 

 TiM-' /s 8 ori Spy "the pletely used up again by the mycelium for the 

 hS s icon- formation of the teleutospore-patches. Spruces 

 and bk s r h are may suffer considerably from loss of foliage 

 stm green, (v. Tubeuf induced by this f unguS) ye t the risks are by 



no means so great as in the case of Chryso- 

 i>ii/.'-<i rhododendri where the whole existence of the plant is 

 endangered. 



Uredospores are unknown for this species and an Aecidium 

 stage has not as yet been discovered. Eeess has shown experi- 

 mentally that the teleutospores germinate directly on spruce 

 without intervention of an aecidial stage. 



Chr. piceae Bare. On needles of Picea morimln in India. 



Chr. empetri (Pers.) (Britain and U.S. America). Uredospores on 

 Eiiip'-t i-ii ni it!<jriim. Cneoma empetri (Pers.) is the aecidial form. 



Chr. pirolae (D. C.) (Britain and U.S. America). Uredo- and teleuto- 

 spores on Pi/rola. Aecidia unknown. 



Chr. albida Kiihn. On Rubus fruticosus in Germany and U.S. America. 



Cronartium. 



Teleutospores unicellular and remaining attached together 

 in the form of a long coiled process; they germinate in 

 xif/i and give off sporidia. The masses of teleutospores arise 

 on the place formerly occupied by a uredospore-sorus. The 

 ovoid uredospores are abjointed from short stalklets enclosed 

 in sori with a short peridium. Aecidia are developed on other 



