CHRYSOMYXA 



311 



Picea e.rcelsa in the North of Europe and has its uredo- and 

 teleutospores on Ledum pcdustre, on which it produces witches'- 

 brooms. See Klebahn, Wirts. Rost. p. 391. It is named by 

 Tranzschel Chrysomyxa Woronini. 



Quite recently also Chrysomyxa Rhododendri has been 

 detected in Scotland by Mr D. A. Boyd. See Appendix. 



1. Chrysomyxa Empetri Schrot. 



Ured<> Empetri Pens. ; Cooke, Handb. p. 527 ; Micr. Fung. p. 216. 

 Chrysomyxa Empetri Schrot. Krypt. Flor. Schles. iii. 372. Plowr. 



Ured. p. 253. Sacc. Syll. vii. 762. Fischer, Ured. Schweiz, 



p. 557. 

 Melampsoropsis Empetri Arthur, N. Arner. Fl. vii. 118. 



Uredospores. Sori hypophyllous, occasionally (according to 

 Magnus) epiphyllous, small, 

 roundish or elongated, some- 

 times arranged in lines parallel 

 to the midrib, covered by the 

 raised epidermis, orange; spores 

 in short chains, ellipsoid or 

 polygonal, densely verrucose, 

 2(3—35 x 18—25 fi, 30—35 x 

 21 — 28//, (according to Fischer), 

 25—30 x 17—25 fi (Plowright), 

 26—37 x 18—26 n (Arthur); 

 wall rather thick, colourless ; 

 contents orange. 



Fig. 235. G. Empetri. a, leaf of 

 Empetrum nigrum, showing three 

 uredo-sori, x 10 ; b, uredospores 

 x600. 



On Empetrum nigrum. Uncommon ; North Wales, etc. 

 May — October. Often in small quantity, and very inconspicuous 

 except when fresh. (Fig. 235.) 



This fungus is considered to be a Chri/somyxa because the uredospores 

 are produced in chains. The teleutospores seem doubtfully to have been 

 observed by Rostrup and Lagerheim, and might possibly be discovered in 

 this country if looked for. This parasite also occurs on the same host in 

 the northern half of North America, but there also no teleutospores have 

 ever been seen. 



Distribution : Europe, North America. 



