368 



UREDINEAE. 



M. salicis-capreae (Pers.) (Britain and U.S. America). 

 Uredo- and teleutospores on leaves of Salix Caprea and several 

 other species. According to Rostrup, Cacoma cuonymi (Gmel.) 

 is a stage of this. 1 



M. Hartigii Tlium. 2 (M. cpitea Thiim.) (Britain and U.S. 

 America). Uredo- and teleutospores on leaves of Salix pruinosa. 

 S. daphnoides, S. viminalis, etc. Rostrup regards C. ribcsii Lk. 

 of liibcs as a caeoma-form. 



FIG. 200. Mi /inii/ixoi-ii .iii/irtx-rttjH-uH. Section through leaf of Snllx Caprea, 

 with a uredospore-sorus on the lower epidermis ; on the upper side a teleutospore- 

 sorus is in process of development, but is as yet completely closed over. (After 

 Tulasne.) 



M. repentis Plowr. :i Uredo- and teleutospores on Salix repens. Cacoma 

 on On-lii'* ni'/i-iilata. (The Caeoma orchidis of other orchids is probably 

 identical with this one.) 



M. arctica Rostr. on Salix kerbacea, S. glauca, and S. groenlandu'n in 

 Greenland. 



M. mixta (Schlecht). (Britain). The related Cueomn is unknown. 



Thiimeii also gives M. Castagnei Tliiiin. on S. amygdalina. 



M. vitellinae D. 0. on Salix fragilis is said by Schroeter to have its 

 Caeoma on ilnliinthus nivalis (Britain). 



The rusts of cultivated willows are very detrimental to them 



1 M. scdicis-capreae (M, caprearum D.C. ) is divided by some authorities into 

 M.farinosa (Pers.) and M. epitea (Kze. et Schni.). 



-See Thiiinen, "Mel. salicina," Mittheilungen aus d. forxtlich. Vemuchswesen. 

 Oesterreic.h, 1879. 



3 Plowright (foe. dt.}. 



