THE FUNGI : ASCOIVIYCETES AND BASIDIOMYCETES 257 



Fig. 248. — Comparison of the perithecia in Erysiphaceae. 

 A, Sphaerotheca. B, Podosphaera. C, Erysiphe. 

 D, Uncimila. E, Phyllactinia. F, Microsphaera. 

 A and B are uniascoid, C to F are multiascoid. 

 {After Heald.) 



form, and we need not consider them here. In fact it is only in the method 

 of formation of the sexual reproductive organs that this species displays 

 an interesting and important difference. 



Conidiospore 



Conidiophore 



_ . Mi. k^ • ^ — ." *■— ., '^ — 





V am fM*. ^" - 



;%v^.^ >'-»-^ .^ . ♦ ' * « 



Fig. 249. — Erysiphe polygoni. Formation of conidiophores 

 on surface of infected leaf. Haustoria may be seen 

 in the epidermal cells. 



