2 A Monograph of the Erysiphaceae 



The limitation of the Family Erysiphaceae to these six genera 

 IS not in universal use. Saccardo in the '' Sylloge '' (307)* divides 

 the family into two sections : Amerosporae, with the characters 

 ''sporidiis ovoideis continuis hyalinis " contains the above six 

 genera; the other, Dictyosporae, ''sporidiis clathrato-septatis " in- 

 cludes the single genus Saccardia. Saccardo has, however, in a 



iD*^ t> 



later work (313) excluded Saccardia from the family.- Karsten 

 (196) creates the sub-family '' ErysipJieae Karst." to include as 

 well the genera Capnodiuui^ Perisporiuni^ Anixia, and Eitrotium, 

 Schroeter (319) includes in the family Apiosporium and Lasio- 

 botrys^ and Jaczewski (176) Etirotium, Apiosporium, Dimcrosponnm, 

 and Microthyrittm. 



The muriform spores of Saccardia seem sufficient to place this 

 genus outside the Erysiphaceae ; Apiosporium^ Dimerosp 



Lasiobofrys, and Capnodium differ in the black mycelium, etc.; 

 Eurotiuui and Anixia are saprophytic ; Perisporium has septate 

 spores, and Microthyritun is far removed in the scutiform, not 

 cleistocarpous perithecia. All these genera, also differ In not 

 possessing the " Oidiiiui " form of conidia. 



The Erysiphaceae belong to the Order Perisporiales of the 

 Class Asconiycetes. In the same order is the Family Perispori- 

 aceae, to which the Erysiphaceae show nearest relationship. 

 The closed pcrithecium, or cleistothecium, as it is sometimes 

 termed, of the present family, must be considered as showing 

 a low degree of development, and places the Erysiphaceae 

 (together with the Peris poriaceae^ among the simplest forms of 

 the Asconiycetes, The characteristic feature of the Erysiphaceae 

 Is their true parasitism : the small size of the perithecia, and 

 the abundant formation of conidia, capable of quickly infecting 

 new hosts, must perhaps be considered rather as being adapta- 

 tions to this mode of life than as primitive characters. Too much 

 significance must not be attached to the presence of appendages 

 to the perithecia. These appendages are strictly homologous to 

 the mycelial outgrowths from the external cells at the base of the 

 perithecium which occur in many genera of the Ascomycetes, In 

 the Family Ascobolaceae of the Order Pezizales these outgrowths 

 (called collectively the "secondary mycelium" by Woronin) re- 



*Tbe numbers refer to the Bibliography given at the end of the vohime. — Ei>- 



