jiiul others, fiiKliiig that those coneeptaeles were liorno on the same 

 iiiyeeliuiu as the ooiiidia and jierithceia, naturally conehuled that they 

 were oi"'M8 of the same plant, and, (roni their analoiiy to certain 

 asexual i roductive bodies in allied ,irron|ts of the Asconnjeetcti, called 

 them pycnidia, and the niinnte l»odies they contain, srtylosporea or 

 pycnidiospores. This is still the accepted Itclier of many botanists. 

 De Ikry (Morph. and Thys. der l^ilze, 111, }.}). 63-75, TaCeln VI, VI I), 

 shows that the jtycnidia instead ol' being reproductive organs ol' the 

 Erysiphc, are, in reality, the IVuctilication ol'a I'ungus that is jiai-asitic 

 on the Eryslphe. lie calls it CIchiobolus. CemtiL and gives numerous 

 (igures showing its delicate, septate mycelium, develojiing within the 

 mycelial threads of the Eryi<ipfH', and sending up branches which, by 

 repeated division, foi-ni the cellular wall of the pycnidium. 



There is much confusion in i-egard to the nomenclature of this 

 group. The earlier authors, with poor magnifiers or none at all, made 

 meager descriptions of their supjiosed species, for which I'oason it is 

 often impossililc to determine from Iheii' writings what they had in 

 hand. I Tost jihints ai'e not so nnich of a guide here as in most cases 

 for parasites, though many specific names have been jtroposed, it seems 

 solely upon the ol)served hal)ilat of the fungus. In what follows, an 

 earnest endeavor has lieen made to identiiy and describe true species 

 wherever they grow. Tlx' l>ullelin of the Illinois State ]jaI)oratory 

 of Natural Ifistory, Volume II, Article A' I, Pardsitlc Fungi of 

 lUinoifn, oai't II, iiy T. ^. Burrill and F. S. Earle. has Itecn made tlie 

 basis of tills woi'k. This bulletin was founded upon collections made 

 in Illinois, mostly by A. H. Seymour who also made studies upon the 

 si)ecies. 



ki;y to Tiir'; ckxkha. 



1 



Appendages to the pei-ithecia simple, and similar 



to the threads of the mycelium. - - - - 2. 



A])i>cndages various, readily distinguished from the 



mycelium. 3, 



Only one ascns in a perithecium. - - Sp/iu'j'otheca. 



Several asci in each i)ei'ithecium. - - - Eryslphe. 



Appendages branched at their tips. - ... 4, 



Ai)i)endages not branched. 5, 



4. Only one ascus in a perithecium. - - Podosphmra. 

 Several asci in each perithecium. - - Mlcrosphmra. 



5. Appendages swollen at base, tips sti'aiglit. Phyllact'mia. 



3 



