166 A Monograph of the Erysiphaceae 



appendices 300-400 /i; asci 4^-45 X 22-50 /i; sporae 14-22 x 

 5-14 />«; conidia 2S-32 x 10-13 /i/' 



I have seen the following examples, of this plant : Jacz.-Kom.- 

 Tranz. Fung. Ross. Exsicc. nr. 79, 'Mn fol. vivis Astragali sp. 

 Ad, fluv. Seravschan (Turkestan)*' ; a specimen in the Herbarium 

 of the University of St. Petersburg, from *' Darch, 6000 feet. 

 Seravschan" super, " on Cohitca crucnta Ait/' ; and a specimen from 

 the same locality as the last, on Cohitca arborcscens, in Professor 

 TranzscheVs herbarium. These two forms on Cohitca and Astra- 

 gahis are sightly different. On the former host-plant the fungus 



forms conspicuous floccose patches, due chiefly to the appendages 

 being more assurgent than usual ; the perithecia are large, 100- 

 i8o/i in diameter, the appendages are 7-28 in number, and very 

 long, reaching sometimes to 8 times the diameter of the perithe- 



cium, not angularly bent, nor nodulose, though very flexuose, usu- 

 ally slightly rough for nearly the whole length ; the apical branch- 

 ing is very wide — often measuring more than 200 fi wide- — and 

 irregular, and the branches are very flexuose and contorted ; the 

 asci are 6-23 in number, with 4-5 spores. On Astragahis the ap- 

 pendages are intricately contorted and angularly bent, but the 

 branching of the apex is often identical with that of the form on 

 Cohitca, although the branches are frequently even more flexuose 

 and curled, the ultimate ones being sometimes almost spirally 

 coiled. Good figures of these two forms have been given by Mag- 

 nus(23i./. <?-/j). 



The characters shown in the branching of the apex, and, in the 

 form on Astragahis, in the peculiar contorted appearance of the 

 appendages, certainly in my opinion, refer '' M. cohitcae'' to M- 

 euphorbiae, I had already, before seeing Komarov's specimens, 

 referred American forms on certain species of Astragalus to M, 

 euphorbiae^ and I now feel convinced that we have this species oc- 

 curring in North America on Euphorbia and Astragahis, and in 

 Asia on Astragahis and Cohctca, 



I have not seen any examples of M. euphorbiac from Europe. 

 Bommer and Rousseau (45) have recorded " Erysiphe euphorbiac 

 Peck," in a conidial stage on Euphorbia amygdaloidcs from Bel- 

 gium ; it is quite possible, however, that this fungus may prove to 

 be Sphacrothcca tomcntosa {S. mors-uvac). European specimens in 



