CHRYSOMYXA. 



379 



occurs on Ledum palustre. It is difficult to distinguish from 

 the preceding species, and causes the formation of similar aecidia 

 on spruces in Northern Germany and other parts where Bhodo- 

 devdron is not indigenous. Its uredospores are also capable 

 of hibernating and of propagating the fungus where spruce is 

 absent. 



Chr. himalayensis Barcl. occurs on leaves of Rhododendron 

 arboreum in the Himalaya. 



Flu. 211. — Ckvyaomyxa rhododendri. Teleuto- 

 spore-sorus which has ruptured the lower epi- 

 dermis of a leaf of RkododendTon hirsutum. The 

 teleutospores are pluricellular, and one of them 

 has germinated, giving a promycelium with 

 sterigmata, from which little sporidia are being 

 abjointed. (After De Bary.) 



Fig. 212. — Chvysomyxa rhododendri 

 on Spruce. The needles are beset 

 with aecidia ; discoloured parts of 

 them are shown black, the normally 

 green being left white, (v. Tubeuf 

 del.) 



Chr. abietis (Wallr.).i Needle-rust of spruce. This is parasitic 

 on the spruce {Picea cxcelsa), and is found on the Alps up to 

 an elevation of over 1*700 metres. About the beginning of 

 May the hibernating teleutospores produce promycelia and 

 sporidia. The latter germinate at once, and the germ-tubes 

 make their way through the epidermis into young unfolding 

 needles. The mycelium is well-developed and lives inter- 

 cellularly, sending haustoria into the host-cells ; it contains 

 yellow oil-drops, so that by the end of June needles contain- 

 ing it exhibit yellow-coloured stripes. For the remainder of 

 the year reddish-yellow elongated teleutospore-cushions are 



^ Reess, Botan. Zeitmig, 1865 ; Die Eostpih/ormen d. deutschen Goniferen, 1869. 

 Willkomm, Die mikroscopiacheii Feinde des Waldts, 1868. 



