212 A Monograph of the Ervsiphaceae 



States, however, the development of ascospores in autumn, or 

 even late summer, appears to be not uncommon. Anderson (6) 

 mentions that ripe ascospores have been found on a species of Poa 

 in Missouri in July, on Beckmannia erncaeforuiis and Hordeurn 

 jubatiDn in October, and on Poa teniiifolia in November, or usu- 

 ally by the middle of October. In a specimen on Poa nenwralis, 

 gathered by Griffiths & Carter in South Dakota in August, I have 

 found 8 well-formed spores in the ascus.. 



A very interesting account is given by Wolff (399) of the de- 

 velopment and germination of the ascopores. This author found 

 that if perithecia of E. graminis containing asci in which no spores 

 are yet formed are placed in water (damp atmosphere, or even a 

 position on water was found to produce no result) they showed, 

 after two or three days, a change in the protoplasmic contents of 

 the asci, leading up gradually, in the course of five or six days, to 

 the formation of usually eight, or seldom only four, spores. 

 These ascospores, like the conidia, were found to germinate read- 

 ily in a damp atmosphere or in a drop of water. In dry air, how- 

 ever, at a temperature of 22°, they perished after i or i ^ hours. 

 Under favorable conditions each ascospore was found to produce 

 several germinating tubes, which at most reached to twice the di- 

 ameter of the spore and A\hich perished if after a period of 30 

 hours at the longest they failed to reach the epidermis of a suit- 

 able host-plant. If, however, this was reached the hyphae pene- 

 trated it and proceeded to form a mycelium in the same manner 

 as those of a germinating conidium, i. e., by first forming a haus- 

 torium, and then spreading from this center. It may be noted that 

 Wolff tried to infect grasses with E. comvmnis {E. polygoni ), and 

 conversely the host plants of E. polygoni {Trifolinm, Dtpinus, etc.) 

 with E. graininis, but without success in either case. 



The perithecia oi E. graminis, \\hQr\ carefully isolated from the 

 persistent mycelium are seen to possess only verv short rudi- 

 mentary appendages ; a few surrounding hyphae c. 

 mycelium often adhere to the perithecia when the latter are taken 

 out, and these hyphae have apparently been mistaken by many 

 authors for true appendages. 



Garovaglio and Cattaneo (143) give an interesting account of 

 the manner in which E. graminis attacks wheat. These authors 



ery 



